NoteVerbaledaie19June1995fiomtheEHibas ofMexico,together
withWittenSment ofthe GovernmenotfMexico The Embassy of Mexico presentç itç compliments to the
President of tne InternationalCourt of Justice and has the nonour
CO forwarà the written statemont by the Governrnent of Mexico on
the requeçt for an adviso-y opinion submitted to the Court by the
Forty-Ninth United Nations General Assembly, through its
resolution 09/75 K.
The above-mentionedwritten statementhas been formulated
~y tno Governrnent of Mexico in accordancewith the order issued by
tnp Court on February 1, 1995, and in conformity with article 66
af the Statute of the Court.
The Embassy of Mexico avails itself of this opportunity
to renew to the Presiàent of the InternationalCourt of Justice
:ne assurancesof its highest consiàeracion.EMBAJADA DE MEXICO
WRlïTEN STATEMENTBY THEGOVERNMENTOF MEXICOON THE REQUEST
FOR AN ADVISORYOPINION SUBMlïTED TO THE INTERNATIONAL COURT
OF JUST~CE BY-THE FORTY-NINTH UNITED NATIONS GENERAL ASSEMBLY
(RESOLUTION49ff5K)
CONTENTS
Surnrnary
Introduction
Expediency of the advisoty opinion
Concept of nuclear weapons
Possession of nuclear weapons
Prohibition on the threat or use of force in international law
Prohibition on the threat or use of nuclearweaponsany circumstance
First use
The threat of first use
Enforcement measures authorized bythecurity Council
Individual or collectivedefense
Prohibition onthe use of certain weapons under international law
International humanitarian law
ConclusionsWRITTEN STATEMENTBYTHE GOVERNMENTOF MEXICOON THE REQUEST
FOR AN ADVISORY OPINION SUBMITTED TO THE INTERNATIONAL COURT
OF JUSTICE BY THE FORTY-NINTHUNITED NATIONS GENERAL ASSEMBLY
(RESOLUTION49175K)
SUMMARY
1. In accordancewith the order issued by the lnternational Courtof Justice on 1
February 1995, and in keeping with the provisions of Article66 of itçStatute, the
Governmentof Mexico hereby submitsto the Court the following written statement
in replyto the request for an advisory opinion,fomulated by the Forty-Ninth United
NationsGeneralAssembly in resolution491 75K, in regardto the following question:
"1sthe threat or use of nuclear weapons in any circumstance petmitted under
internationallaw?"
2. This wriien statement will answerthe question presentedto the Court in the
negative. It will demonstrate that, by contravening the noms of international law
currently applicable to the maintenance of international peace and securîty and
international humanitarian law. the use or the threat of use of nuclear weapons is
underno circumstance perrnittedby intemationallaw.
3. In this regard. it should be noted that on 9 June 1994 the Government of
Mexico submitted a written statementto the lnternational Court of Justice regarding
the request for an advisory opinion fomulated by the World Health Organization in
resolution WHA 46.40. on the following question: "ln view of the heaith and
environmentaleffects, would the use of nuclear weapons bya State in war or other
armed conflict be a breach of its obligations under international law including the
WHO Constitution?" Althoughthe aforementionedwrittenstaternentfocused onthe
content of the norms applicable to arrned conflicts (jus in bello), the question
formulated to the Court in United Nations General Assembly resolution 49/75K
rneritsscrupulous analysisof the law on the maintenanceof internationalpeace and
security.
4. In this written statement, the Governrnentof Mexico will place emphasis on
the norms of international law currently applicable to the maintenance of
international peace and security, as well as of the law of armed conflictç. These
norms are rnainly contained in the Charter of the United Nations, in multilateral
treaties and in declarations and resolutionsadopted bythe principal organs of the
UnitedNations. Wfih reaardto the latter.the Governmentof Mexico recoonizes 0-e - ~ -
declarations and resolutTonsquoted in this written statement as noms of general
international law, due to the fact that they either reproduce existing c-stornary
norms or have contributedto their consolidation.
INTRODUCTION
5. No threat is more imminent to the maintenance of international peace and
security and to the survival of mankind itself than the very existence of nuclear
weapons. The warlike nature ofthis type of weapons. theirdestructive capacity and
their effects on al1forrns of life on earth, are more than enough to justi their
disappearancefrorn the world scene. nuclear disarmamentforangseveral decades. At present, therefore, total elirnination of
nuclearweapons isone of the internationalcommunity'spriority cornmitrnents.1
7.
Despite the fact that intenational law has been addressing the issue of
use ofrsuch weapons has yet to rneet with success. As will be dernonstratedon the
throughout this document, the absence of an express prohibition has proved
irrelevant and, consequently,turn out to be insufficientto generate any presurnption
of the legalty of the use or threat of the use of nuclear weapons. The noms
applicable to amed conflicts and to the maintenance of international peace and
security, which are of a legally binding nature for al1the States (juscogens), are
more than sufïicient to state without question that the use or threat of the use of
nuclearweapons isunder no circumstancepennitted by international law.
EXPEDIENCYOF THE REQUEST FOR ANADVISORYOPINION
8. By its very nature, the international systern frequently faces situations 'in
which the extent of the legal noms applicable to relations between States is not
altogether clear. In such situations, delimiting the content of international law
becomes an especially important task inwhich the lnternational Court of Justice
rnakesa highly signitïcantcontribution.
9. The need to specrfythe scope of the noms of international law is particularfy
evident in the case of nuclear weapons. The increasinglydestructive capacity of this
type of weapon poses an exceptional threat to internationalpeace and security and
also, evidently, to thefulfillment of the Principles and Purposesof the Charter of the
United Nations. It therefore cornes as no surprise that since the UN initiated its
efforts,ithas placed special emphasis on promoting disamament and on seeking
the eiirnination of nuclear weapons and weaponsof rnassdestruction frorn national
arsenals.2
10. Nuclear weapons, however, are regulated by international law in several
manners. Rules have been established on prohibitingthe use of nuclear weapons
in certain regions,3 prohibiting nuclear proliferation,4 partially .banni119nuclear
testing,5 etc., and it is precisely such wide-ranging regulationsthat have led States
to uphold different positions with regard to the use or threat of the use of nuclear
weapons.
11. Bearing in rnind the importance to the international community of this topic
and the differences in the approach taken towards it, the opinion of a judicial organ
as important as the lnternational Court of Justice would provide the States with an
authoritativeanswerto a questionof internationalimport,and. evidently, with a more
effective basis for progress in international CO-operation towards nuclear
disarmament.
12. It is not hard to perceive the political aspect of the topic submitted to the
considerationof the Court. Nevertheless.theessentiallylegalnature of the question
formulated makes the lnternational Court of Justice the competentbody in which to
elucidate the issue. This is notthe first time requestsfor advisory opinions having a
significant amount ofpolitical opposition havebeen submittedto the principaljudicial
organ of the United Nations.6 yet the Court has in every case fulfilled the
internationalcornrnunrty'sexpectations.
13. The Government of Mexicoconsidersthat the Court has been presented with
an invaluable opportunity to support other organs of the United Nations incarrying
out their duties,7 white at the sarne tirne contributingto further clariiying the nomsof international law. We are sure that the Court will take the best possible
advantageofthis opportunity.
THECONCEPTOFNUCLEARWEAPONS
14. The question formulated tothe Court calls for a definition of the meaning of
the tem "nuclear weapon." To that end, we rnay refer to sorne of the definitions
used in the internationalsphere:
15. Article5 of theTreaty for the Prohibition of NuciearWeapons in LatinArnerica
and the Caribbean (lreaty of Tiatelolco) defines nuclear weapons as "...any device
which is capable of releasing nuclear energy in an uncontrolled manner and which
has a groupof characteristicsthat are appropriatefor usefor wariike purposes."
16. The Treaty on a Nuclear-Weapon-Free Zone in the South Pacific (Treaty of
Rarotonga)defines as an "explosive nuclear device" any nuclear weapon or other
explosive device capable of releasing nuclear energy, irrespective of the objetiwe
for whichsucha weapon may be used.
17. The tem is also used in a generic sense in reference to atornic or hydrogen
weaponsof ailtypes andto their delivery systerns.8
18. As may be appreciated, although the definitions differ as to tenninology, al1
focus on artifacts of rnassdestruction which function on the basisof nuclearenergy.
includingtheir delivery systems. The aim of this document is to analyzethe use or
threat of the use ofsuchinstruments.
POSSESSIONOF NUCLEARWEAPONS
19. Before embarking on the analysis of the illegality of the threat or use of
nuclear weapons, it is fundarnental to disrniss at the outset that the possession of
nuclear weapons by Nuclear Weapons States (NWSns) penits such States to
threat or usesuch weaponsagainstother States.
20. Certain States have sought to legitirnize the use or the threat of use of
nuclearweapons on thegrounds that the Treaty on the Non-Proliierationof Nuclear
will be demonstratedbelow, possessionof nuclearweapons isss ssolely ternporaryand
initial,and doesnot legitimizethethreat or the use of such~ea~ons.~
21. Althoughthe NPTis generallyperceived as an instrumentvital to international
security, it led to the establishment of a discriminatory regime among the States
parties by penitting the five declared nuclear powersto possess nuclearweapons
while prohibitingthe rernainderto possess them.
22. In orderto elirninatethis discriminatory regirneand attain a balance between
the rights and the obligations of the Parties, the States undertook to pursue
negotiations in good faith on effective measures relating to the cessation of the
nuclear arms race at anearly date and to nuclear disarmament, and ona Treaty for
general and complete disanament under strict and effective international control
(Article VI). Furthennore, the Prearnble to NPT callsfor the liquidation of al1their
existing stockpilesandthe elirninationfrom national arsenals of al1nuclearweapons
and their rneansof delivery.
23. Accordingly, possessionof nuclear weapons and, hence, the discriminatory
regirneof NPT,can onlybe interpreted as being ternporary, untilthe ultirnategoal ofEBXBAJADA DE MEXICO
cornplete elirninationof such weapons is attained. Onthe other hand, possession of
nuclear weapons bythe five declared NWS had to be tolerated, but never accepted,
as an initial step to start therefrom the efforts to achieve the ultirnate goal of the
Treaty, general and cornpletedisamarnent.
24. In this regard,the Decision adopted without a vote at the recent 1995 Review
and Extension Conference of the Parties to the NPT.10whereby the Parties decided
that the Treaty will continue in force indefinitely, could never be taken to rnean
legitirnizing possession of nuclear weapons in an indefinite rnanner. Mexico's
staternent at the tirne of adoption of the decisions adoptedby consensus reiterated
that an indefinite extension of NPT did not mean the perpetuationof the dichotorny
between Nuclear-Weapon States and Non-Nuclear-Weapon States, since the
Conference had reaffimed inthat context that the uitimate goal of NPT is the total
elirnination ofl1nuclearweapons.11 Thus, by reiteratingthat goal, the existence of
nuclear weapons is clearly not legitirnized by the intemational cornmunrty and the
use or threat of the use of such weapons would be contraryto international law.
25. In point of fact, the programme of action ernbodied in the Decision on the
principles and objectives for nuclear non-proiiferation and disamarnent12
conternplates the detemined pursuit by the Nuclear-Weapon States of systernatic
and progressive efforts to reduce nuclear weapons globally,with the ultirnate goal of
eiirninatingthose weapons. and by al1States of general and complete disannarnent
under strictand effective international control.13
26. In this regard, the nuclear disamarnent obligations contained in the Treaty
have equally taken on indefinite force until they are fully cornplied with, and the
organized international comrnunity will continueto work in favour of the abolition of
nuclearweapons.
27. The Court rnayalso wish to considerthe Final Documentofthe Tenth Special
Session of the General Assernbly Devoted to Disanament of 1978, in whose
prearnble it was stated:
"The GeneralAssembly,
"Alanned by the threat to the very survival of rnankind posedby the existence
of nuclear weapons and the continuing arrns race, and recalling the devastation
inflicted by al1war..."
Further below. the first operative paragraph of the Final Document declared
that:
"...the accumulation of weapons. particularly nuclear weapons, today constitutes
much more a threat than a protection for the future of rnankin..."
28. Necessarily, once the international cornrnunQ has determined the threat
nuclear weapons represent to the survival of rnankind, it can be sustained an
argument leading to deny that international law pemits the poçsesion of such
weapons. It is worth mentioning that the Final Documentwas adopted unanimously
and it is so far an obliged reference of the multilateral negotiationstaking place in
the Conferenceon Disannament.
29. The threat posed to the survival of rnankind by the existence of nuclear
itself on the illegality ofh weapons and to act accordingly above any sovereigne
rightthat a State rnayclairnto acquire any means
its defense. Certainly, Nuclear-Weapon States cannot clairn that this questionee
belongs to its intemal jurisdiction. The Charter of the United Nations undoubtedlyestablished as its principal purpose the maintenance of intemational peace and
securiiy. The mere possesion of nuclear weapons.runs contrary to the security of
mankind.
PROHIBITIONON THE THREAT OR THE USE OF FORCE IN INTERNATIONAL
LAW
30. One of the basic noms for the fuffillment of the Principles and Purposes of
the Charter of the United Nations may be found in the proscription of the threat or
use of force against theterritorial integrity or political independenceof any State, or
in any other manner inconsistent with the Purposes of the United Nations, as
contained in paragraph 4 of Articl2ofthe above-rnentionedinstrument.
31. The fundamental obligationof the States is to refrainfrom usingforce and to
settle their disputes by peaceful means. As may be inferred from the paragraph
quoted, the aforernentioned prohibitionis not only limited to the use of force, but
alsoto the threat, and not only to the territorial integrity or polical independence of
any State. but alsoto any othermeansincompatible withthe UnitedNations. Sin'ce
those airns include the maintenance of peace and the development of friendly
relationsamongStates, the possibili of resortingto thethreat orthe use of force is
practically forbidden. The threat or use of nuclear weapons is necessarilyincluded
within the bounds of that prohibition, and its actualiationwould therefore be
contraryto intemationallaw.
32. The prohibition on the threat or use of force contained in the Charter has
been reaffinned by numerous resolutions and declarations adopted within the
framework ofthe United Nations. The following are amongthe mostprominent:
a. The Declaration on the principles of international law conceming friendly
relations and CO-operationamong States in accordance with the Charter of the
United Nations (resolution 2625 (XXV), annex), reiterates the language ofArticle2
(4) othe Charter,and adds:
"Such a threat or use of force constitutes a violation of internationallaw and of the
Charter of the United Nations andshall never be employed as a means of settling
internationalissues."
"A war of aggression constitutes a crime against the peace, for which there is
responsibilityunder internationallaw."l4
b. The Declarationof Manilaon the peaceful settlementof internationaldisputes
(resolution37/10,annex) establishesthat: IEvery States shall settle its international
internationalpeaceand security,andjustice, are notaendangered."lsure that
c.
refraining fromthe threat or useof force in international relations (resolu42/22,
annex). in additionto reiteratingthe content of Article 2 (4)of the Charter,adds that
such a principle is universal in character and is binding regardlesf each State's
politicai,economic.social or culturalsystern or relations of alliancFurthemore.
it establishes that no considerationof whatever nature may be invokedto warrant
resortinqjo the threat or use of force in violation of the Charter of the United
Nations.
33. As stated earlier, proscription of the threat or use of force in international
relations is a generic prohibition that necessarily includes nuclear weapons.
Additionally, the United Nations GeneralAssembly has adopted various resolutionsEXBAJADA DE MEXICO
which expressly state the prohibition on the threat or use of nuclear weapons. The
following areamong the most important:
a. By virtue of the Declaration on the prohibition of the use of nuclear and
thermonuclear weapons (resolution 1653 (XVI)),the General Assembly declared
that the use of nuclear and thermonuclear weapons constiiutes a violation of the
Charter, as acting contrary to the laws of humanity and as committing a crime
against hurnanity and civilization.That condemnation was reaffirmed by means of
resolutions 33/71B, 34/83 G, 3511220,36192 1,45169Band 46/37 D.
b. The Declaration on intemational CO-operationfor disarmament (resolution
34/88) called upon al1the States not to use their miiiirv Dower for aaaressive
purpkes, especially by applying force or threatening fo 'apply li&agshst the
sovereignty.territorial integrity or political independenceof any State.
34. The Charter of the United Nations and the aforementioned resolutions make
no distinction between the legal status of the threat of use of force and the use of
force itself.60th situations are prohibied equally. In practice, however, greater
emphasis has been placed on prohibiing the use of force. In cases in which the
threat is actualized by the use of force, the attention will necessarily focus on the
latter aspect. In any event. proscriptionof the threat of force will apply evensuch
a threat has not led to the use offorce.
35. One way of explaining the dficuky involved in determiningthe existence of a
threat of use of force rnay be found in the mechanism which establishes the
existence of a threat to internationalpeace and security, as contained in the Charter.
Inaccordance with Article 39, the Security Council is responsiblefor determining the
existence of any threat to peace, breach of the peace or act of aggression. The
rightto veto held by the five permanent members of the Council (which at the same
time are the five declared nuclear powers), would procedurally hinder determining
the existence of a threat, shouldone of those powers be involved. The impossibility
for the Council todeterrnine the existence of a threat of use of force due to the
interposition of a veto, does not reduce, however, the legal force of the prohibition
on any threat.
36. The Secretary-Generalof the United Nations,for his part, has indicated that
the threat of useof force occurswhen a State. in order to impose its will on another
State,threatens to use force against that State. He has also specified that such a
threatdoes not necessarily have to be made openly, but at on certain occasions
veiledthreats could be most effective,yetdifftcultto prov$.
37. The ternational Law Commission has considered the "threat of
aggression''2pa crime against the peace and securii of mankind and has included
it as an articleseparate from "aggr ion" within the draft Code of Crimes the
Commission is currently working onyF Article 16 of the Code establishes the
following:
"1. An individual who as leader or organizer commits or orders he
commission ofa threat of aggression shall, on conviction thereof, be sentenced.23
"2. The threat of aggression consists in declarations, communications.
demonstrations of force or any other measures which wouldgive good reason to the
Government of a Syte to believe that aggression is being seriously conternplated
againstthat State."
38. Characterization of the threat of aggression as a crimeagainstthe peace and
security of mankind bythe International Law Commission reflectsthe status that theconcept has attained in intemational law. and is considered by experts to be the
codificationof a rule of internationalcustomarylaw.
39. Although both the threat of use of force and the use of force itseif are
prohibitedunder internationallaw, the legal effects produced byeither situation will
have implications on the Goncept of seif-defense. The international Law
Commission has specified that the "threat of aggression" does gtt, give rise to
individual orollective seif-defense under Article 51 of the Charterincontrast to
aggression itself.
PROHIBITIONON THETHREAT OR USE OF NUCLEARWEAPONS UNDER ANY
CIRCUMSTANCE
40. The concepts setforth aboveleadto the definitiveconclusion that there exists
a rule of international law prohibiiingthe threat or useof force, includingby means
of nuclear weapons. Nevertheless,the threat or use of force by means of nuclear
weapons may arise under various circumstances, which, once reviewed. would
make it possible to prove that the threat or use of nuclear weapons is not
pennitted inany circumstanceunder international law.
Firstuse
41. As a direct consequenceof the general prohibition on the threat or use of
force, a first nuclear attackwouldviolate the terms of Ar2(4)of the Charter and
would also, therefore, be contrary to international law, whether camed out against
another Nuclear-Weapon State (NWS) or a Non-Nuclear-Weapon State (NNWS).
The Declaration of the GeneralAssembly on the prevention of nuclear catastrophe
(resolution 361100)sets forth that "States and statesmen that resort firstto t% use
of nuclear weapons will be committingthe gravest crime against hurnanity." So
far, the People' Republicof China is the only State that has adopted anficial no-
first use poli36.
42.
rule containedin Article 2 (4) of the Charter, but also merit stronger sanctions under
international law by constiuting a breach of th underlying principle of
proporfionalityestablished by the law on aned conflicts.
43. SecurityCouncil resolution984 (1995) andt%declarations of NWSns setting
forth positive and negative securi assurances, represented a step forward
towards providing NNWSns with assurancesagainst the use andthreat of the use
of nuclear weapons. Those security assurances have nevertheleçs proved
insufficient,since they were notgrantedin a certain, unrestrictive,unconditional and
non-discriminatoryform.
44. Accordingly, the Decisi on principles and objectives for nuclear non-
proiiferation and disamament!B adopted without a vote by the 1995 Review and
Extension Conference of the Parties to the Treaty on the Non-Prolieration of
NuclearWeapons (NPT), notingresolution 984 (1995) as well asthe declarations of
NWSiIs on positive and negative security assurances, indicated that further steps
should be considered to assure NNWSns party to the Treaty against the use or
threat of the use of nuclearweapons, whichcouldtake the forrn of an internationally
legallybinding instrument.
45. Although to date the Conference on Disarmament has been unable to
negotiate a legally binding instrumentcontaining assurances of universal scope to
NNWSns against the use or threat of the use of nuclear weapons, the purpose of
resolution 984(1995) andthe intentof the States partiesto the NPTcontained in theEXEAJADA DE MEXICO
Decision mentioned in the above paragraph, implicitly recognize the illegality of the
threat or the use of nuclear weapons against a NNWS. Obviously, were the threat
or the use of nuclear weapons a legal ad, negative security assurances to protect
NNWSîIs would have been unnecessary.
46. Despite the absence of a legally binding instrument on negative security
assurances of universalscope, it should be borne in rnindthat inAdditional Protocol
II of the Treaty of Tlatelolco, the five declared NWSns undertook not to se or
threaten to use nuclearweapons againstthe Contracting Partiesto the Treaty.
Thefhreafof first use
47. A threat of first use could arise in a confiict, either by threatening a
~reem~tive nuclear strike aaainst a mrceived threat of nuclear attack. or bv
ihreatening a nuclear strike against a possibleattack by conventionalweapons or bi
threatening a response to an actual conventional attack.
48. The threat of first use is a violation of the prohibition on the threat of use .of
force contained in Article 2 (4) of the Charter. Thethreat of first use is intrinsically a
threat against the politicalindependence or territorialtegrity of another State. Any
State either in cuvent or potential conflict wiîh a nuclearState advocatinga policy of
firstase recognizes the threat posed by nuclearweapons and the possibility of their
being usedagainst it. Dueto the unique nature of nuclear weapons, as weapons of
rnass destruction, they repreçent a threat of unequaled intimidation which would
undemine the politicalindependenceof the threatened State.
49. The only exceptionsestablished by internationallawto the general prohibition
on the threat or use of force in relations between States are to be foundinChapter
VI1of the Charter. These exceptions are the enforcement measures authorized by
the Securii Council, and individualor collectiveself-defense.
Enforcernentrneasuresauthonzed by the SecurityCouncil
50. For the mechanisrn of collective security to enter into e ct there rnust be a
threat to peace. abreachof the peace or an act of aggression3 ln any such case.
the Security Council will be responsible for deciding and following up on the
rneasuresto be adoptedto restore internationalpeaceand security.
51. Once the mechanism of collective securrty had been activated. it would be
impossible for the SecurityCouncilto authorizethe use of nuclearweapons against
a State. Two arguments reinforce the above statement: first, the Security Council,
being the organ that holds the primary responsibility for the maintenance of
international peace and security, could not contemplate -even theoretically-
authorizingthe use of weapons of mass destruction whose dgmctive effects on al1
forrns of Iifeon the planethavebeen scientificallydeterrnined.
52. Secondly, the General Assernbly has adopted a number of resolutions
declaring that the use of nuclearweapons constitutea violationof the Charter of the
United Nations and a crimeagainst mankind (seeparagraph 33 a. supra). Clearly, if
the General Assernbly has condemned the use of nuclear weapons, the Security
Council is precluded frornauthorizingtheir use.
53. Therefore, Security Council resolutions 255 (1967) and 984 (1995), which
provide that aggression or the threat of aggressionwith nuclear weapons against a
NNWSwould require the Security Council,and above al1its permanent rnembers. to
act immediately in accordance with their obligations under the Charter, would
necessarily have to be appliedtotally outside the realm of resorting to the threat or
use of nuclearweapons.lndividual or collective self-defense
54. Article 51 of the Charter States: "Nothing in the present Charter shall impair
the inherent right of individual or collective seif-defense if an anedattack occurs
against a Member of the United Nations. until the Securiiy Council has taken
measures necessary to maintain international peace and securiiy..."
55. The intent of the above-mentioned provision is clear: any State has a
legitimate right to~ake use of force to defend itseif when it becornes the victim of
an aned attack, and other States may join in assisting the victirn white the
Security Council acts to fuifil1the duties entrusteditunder the Charter.
56. lndividual or collective selfdefense is conceived as a means of preserving
essential rights against irreparable damage when no other means of protection
exist, and its exercise is therefore not absolute. Observance of the restrictions
international law has irnposed on ser-defense is indispensable in maintaining its use
within a framework of legaiii.
57. The right of seifdefense is actuaiiied only when the need for defense is
immediate and overwhelming, and is considered legal when proportional to the
arrned attack that gave riseto such defense.
58. The International Law Commission has defined proportionaiii by stating that
the size of the measures adopted by an injured State should be comparabjfi to the
graveness of the internationally illega! act it is facing and to its effects. This
means that seif- defense cannot be excessive.
59. Necessrty is the justification for an action involving the use of force. This
means that unlesscertain measures are adopted against a Statethat has committed
an act of aggression, essential rights of the aggrieved would be destroyed.
Nevertheless,justification does not allow discretionaltty. and only such rneasuresas
are strictly necessary to put an end to the attack could be adopted under the tiile of
self-defense.
60. As may be appreciated. the requirements of proportionality and necessityare
concurrent. Necessity justifies the action, butthat action cannot exceed thelimits of
proportionality andshould cease as soon as no longer necessary. The legitimacyof
the actions adopted under the concept of self-defense depends on the observance
of the principles mentioned above.
61. The use of nuclear weapons in case of self-defense is not pemitted under
international law, owing to the fact that such use contravenes the principles of
proportionaiii and necessrty on which the legal nature of the aforementioned
concept is based. In this regard. and to reafirm the above, a distinction should be
made between two situations in which the use of nuclear weapons could take place
under this title: as a result of an act of aggression using conventional weapons or as
a reaction against a nuclear strike.
62. In the first case, there is no doubt that a reaction using nuclear weapons to
an attack perpetrated with conventional weapons violates the ggnciple of
proportionality, which by definition is incompatible with mass destruction.
63. In the second case, the illegality of the nuclear response would violate other
fundarnental principles of international law, among the rnost prorninent of which are
those applicable to armed conflicts (see paragraphs, 77'and 78 infra)Although in
theory the use of nuclear weapons could be justified by the provisions of Article 51
of the Charter of the United Nations and by applying the rules of international lawE-UBAJADA DE MEXICO
established by The Carolina (any action of self-defense should fulfill the
following conditions:an instant and overwhelmingnecessity for selfdefense, leaving
no moment for deliberation and no choice of means, and be proportional), such a
justification would be highly questionable. Even by actuaiiiing the requirement of
absence of deliberation or choice of means. the condition of proportionaldy would
not be respected. since in the case of a nuclear attack the proportionality of a
nuclear response would be uncontrollable andwould endanger the security of
mankind as a whole.
64. Clearly, moreover, there is no possibilii of resorting to self-defense to justii
a first-use nuclear attack in cases of threat of the use of nuclear or conventional
weapons, since, as stated earlier, there is no legal possibilii of resorting to self-
defense incases of threats.
65. It should be borne in rnind that the principal purpose of the United Nations,
according to the Preamble of the Charter, is 'Io save succeeding generations from
the scourge of war, which twice in our iifetime has brought untold sorrow to
mankind." This purpose would clearly be frustrateci if a State which had been
subjected to nuclear attack were to retaliate in kind, sincethe likely outcome of such
an exchange would be the massive destruction of lie in both States, on the
population of neighbouringStates and excessively hamful effects on heatth and the
environrnent in the rest of the world. Therefore, the second use of nuclear weapons
is not perrnissible. whether in retaiiation or selfdefense, since defensive military
actions is subject to the law of anned conflicts to the sarne extent as offensive
actions.
66. With regardto the use of nuclearweapons as a meansfor reprisals, self-help,
counterrneasure. or, broadly speaking, in response to a violation by a State of an
obligation stipulated in international law, it is possible to state that such use runs
counter to internationallaw and is inconsistent with the Principles and Purposes of
the Charter ofthe UnitedNations.
67. The Security Council has stated on a number of occasions37 that reprisals
involving the use of force are prohibitednder international law. Furthennore. the
Declaration on the principles of international law concerning friendly relations.and
CO-operationamong States in accordance with the Charter of the United Nations
(resolution 2625(XXV),annex), indicates that Stateshave a duty to refrain from acts
of reprisa1involvingthe use of force.
68. The lnternational Law Commission, for its part. has provided that
contemporary international lawdoes not perrnits neither reasonablyarmed reprisals,
nor forms f self-help involving the use of force, nor arrnedintervention based on
necessity.3%
69. Finally. the International Court of Justice re. cted arguments of self-help or
international law. the Case of theCorfu channet!% considering them contrary to
70. There being no further need to enlarge on the subject, suffice it to Saythat
save for the exceptions to the prohibition on the use of force contained in the
Charterof the United Nations(see paragraphs50 to 65 supra),any unilateral action.
regardless of its nature,involvingthe use of force, is prohibited byinternational law.
PROHIBITION ONTHE USE OF CERTAINWEAPONS IN INTERNATIONAL LAW
71. The notion of expressly prohibiting the use of certain weapons first arose in
the Declaration of Saint Petersburg of 1868. That document stated that theEXBAJADA DE MEXICO
Droaressof civiliation should have the effect of rnitiaatinathe calamities of waras
inuih as possible, and prohibited the use of any p6jectik weighing less than 400
grammes or loaded by means of fulrninatingor inflammablesubstances.
72. The Declaration of Saint Petersburgwas followed by a series of international
instruments in which the idea of preventing unnecessary suffering andsuperfluous
damage to the enerny led to a prohibition on the use of certain weapons. Such
instruments included The Hague Conventions of 1899 and 1907, which prohibited
the use of poisoned or poisonous weapons and of ams, projectiles or materials
causing unnecessary suffering;the Protocolof 1925for the prohibition of the use in
war of asphyxiating, poisonous or other gases, and of bacteriological methods of
warfare (The Geneva Gas Protocol); and the Convention on the prohibition of the
development, production and stockpiling of bactenological (biological) and toxin
weaponsand on their destructionof 10Apnl 1972,etc.'
73. All the above-rnentionedinstruments have made it ciear that the nght of the
parties in an amed conflict to choose the rneans of haming the enemy is not
unlirnitedand is, in fact. subjectto restrictions. In this regard, it is worth highligwing
Article 35 of the Protocol Additional I of 19ïï to the Geneva Conventions of 12
August 1949, and relating to the Protection of Victirns of International Amied
Confiicts, whichreaffims that the right of the Partiesto an amed conflict to choose
methods or means of warfare is not unlirnited and that it is prohibiied to employ
weapons, projectiles and matenal and rnethods of warfare of a naturs to cause
superfluous injury or unnecessary suffering. It also addsa prohibition against the
ernployment of methods or means of warfare causing widespread,long-tem and
severe damage to the natural environment.
74. Certain States consider that the provisions of Protocol Additional I exclude
nuclear weapons frorntheir scope of application. It is held, however,that such an
affirmation is unfounded. In the first place, because such an exclusion does not
follow frorn the text of the said instrument. and even if itdid. international
humanitarian law has evolved in such a manner since the adoption of Protocol
Additional I that it is impossible to affirm that its provisions merely extend to
conventional weapons. In the second place. even if a reservation in relation to
nuckar weapogâ did exist, itwould be incompatiblewith the object and purpose of
the instrument.
75. The international cornrnunity considers that certain types of arrnarnents
should be prohibited on account of their inhumane effects on individuals. However,
none of the effects produced by the weapons expressly prohibited by international
law can compare with those stemmingfrorn the use of nuclear weapons. Clearly, if
weapons with lessereffects than those of nuclear weapons have been banned, al1
the more reasonto extend sucha banto nucleararmaments.
76. To consider that the absence of a prohibition in international law directed
specifically at nuclear weapons means that their use might be lawful, is ngy only
unacceptable, butalso queriesthe credibilityof the internationallegalsystern.
INTERNATIONAL HUMANITARIANLAW
77. It is also important to analyze the rules of internationalhumanitarian law in
order to confirrn the illegalrtyof the threat or the use of nuclear weapons. Clearly, if
we accept the principleby whichthe use of any weapon is legitimateonly as far as it
is ernployedto defeat the enemy,whether or not in self-defense,we could not even
think that international law permits the possibility to defeat the whole of mankind.
The nature of the effects stemming from the use of any kind of nuclear weapon
stands as one of the strongest argumentsto support on the illegalityof the threat orE.UBAJADd DE MEXICO
International hurnanitarian law has elaborated on the
the use of nuclear weapons.
principles rnentioned below, al1of which will lead to the conclusion that the threat or
the use of nuclear weapons is not pemitted in any circumstancein international law,
including in case of an arrned conflict.
a. The principle of moderation. According to this principle the right of
belligerents to adoptmeans of injuring the enerny is not unlirnited. This principle is
contained in Article 22 of the Regulations annexed to the The Hague Convention IV
of 1907 and Article 35 of ProtocolAdditional Iof 1977to the Geneva Conventions of
12August 1949.
b. T e principle of humaniîy (De Martens Clause). By virtue of the De Martens
the provisions of the Protoml Additional Iand the Geneva Conventions
are applicable in any circurnstance regardlessof the unfavorable nature or origin of
the arrned conflict or in the causes invoked by the Parties toa conflict. Therefore,
the first use of nuclear weapons would be encompased under the scope of the
above rnentioned inst~rnents in accordancewith the Clause.
On the other hand, the principle of hurnanity, mntained in the Preamble of The
Hague Convention IV of 1907 and in Article 1.2 of the Protowl Additional 1,
establishes that in those cases not expresslyforeseen in such instruments. civilians
and belligerents are under the protection of the law of nations stemrning from the
usages, the principles of the hurnanity and the dictates of public conscience.
Therefore, the illegali of nuclear weapons depends on the principle of hurnanity.
There are sacred rules that cannot be violated, even if the enerny has breached
them previously. Thus, Pictet when speaking of the prohibition on al1reprisais
against protected perçons by the Geneva Conventions says: "LfIinterdiction des
represailles ainsi établiea un caractère absolu. Elle vaut même si la violationa
laquelleO prétendre répondresnest produite dans le champ des Conventions de
Genève". 43
c. The principle by which it is forbidden the use of weapons,projectiles, material
and methods of warfare of a nature to cause superfluous injury or unnecessary
suffering. It is worth highlighting that regardless of the degree of improvernent of
nuclearweapons, dueto the suffering infringed uponthebelligerentsand the civilian
population, these weapons will always cause excessive damages and will have
indiscriminateeffects. even in sites far frorn the scene ofoperations (SeeArticle 23
of the Regulations annexed to The Hague Convention IV of 1907 and Article 35 of
ProtocolAdditional I of 1977).
It is also relevant the fact that the Protocol of 1925 for the prohibition of the use in
war of asphyxiating, poisonous or other gases, and of bacteriological rnethods of
warfare (The Geneva Gas Protocol) is applicable to nuclear weapons even if it was
"If it could be established that the use of ail nuclear weapons involved necessarily
the discharge of gases ennumerated in the Protocol, it would settle matters
conclusively bettweenthe Parties to the Protocol. Even if the words "al1analogous
liquids, rnaterials or devices" are so comprehensively phrased as to include any
weapons of analogous character. irrespective of whether they were known or
induced at the tirne of the signature of the Protocol. If the radiation and fall-out
effects of nuclear weaponscan be likenedto poison,allthe more can they be Iikened
to poison gas which is but an even more closely analogous species of the genus
poison".44
d. The principle by which the civilian population enjoys general protection and
the prohibition tocany out indiscriminate aitacks. In accordance to international
humanitarian law, indiscriminate attacks are those that can reach both military
targets and civilians. Nuclear weapons are essentially weapons of indiscriminateefiects, irrespective of the concrete circumstancesof its use (Arti51e of Protocol
Additional I of 1977).
78. In light of the aforementioned considerations, in the opinion of the
Governmentof Mexicothe generalprinciplescoditïedin the Regulationsannexedto
The Hague Convention IV, the Protocol Addional 1 of 19T7 to the Geneva
Conventions of 1949 and in the Preamble of the Convention on prohibition or
restriction on the use of certainconventionalweapons whichmay be deernedto be
excessively injurious or to have indiscriminate effects of 1980, are peremptory
noms of general international law (ius cogens) as established by the Vienna
Conventiononthe LawofTreatiesof 1969.
CONCLUSIONS
79. The above paragraphs lead to the conclusion. that in accordance with
international law relating to the maintenance of international peace and
security, to amed conflicts and to other obligations subscribed by the States
on disannament issues, the threat or use of nuclear weapons is not pennitted
by international law under any circumstances. The scope of the obligations
that constitute the grounds for this conclusion make it evident that no
circumshnce whatsoever would justify the threat or use of nuclear weapons.
80. The body of international law on which such a prohibition is based is
made up of conventional and customary noms, including peremptory noms
of general international law by virtue of which the threat or the use of
weapons of rnass destruction could not be legitimized. On the contraiy, the
treaties and resolutions of United Nations Ornans. reinforced bv the curre.- -
status of applicability of noms on the maintenance of international peace and
security, point to theultirnate goal of total elimination of al1nuclear weapons.EMBAJADA DE MEXICO
NOTESAND QUOTATIONS
1. See. for exarnple, the Prearnble and Article VI of the Treaty on the Non-
Proliferationof NuclearWeapons (1 July 1968).
2. See, for example. Article 11 of the Charter of the United Nations and
resolution l(1) of the GeneralAssernbly,adopted unanirnouslyon 24 January 1946.
3. Among thern, the Treaty for the Prohibition of Nuclear Weapons in Latin
Arnerica and the Caribbean (14 February 1967) and the Treaty on a Nuclear
Weapon-Free Zone inthe South Pacfic (6 August 1985).
4. Treaîy on the Non-Prolieration of NuclearWeapons.
5. Treaty banning nuclear weapon tests in the atrnosphere, in outer space and
underWater (5 August 1963).
6. See RosseneShabtai: The WoddCourt: Whatit is andhow it works, 1989. p.
106.
7. In particular, the First Cornmittee of the General Assernbly and the
Conferenceon Disarmarnent.
8. United Nations. Disannament Topics: Towards a Nuclear Test Ban, New
York, July 1989, p. 22.
Therefore, it should be rejected the argument presented by sorne NWSns by
which it is clairned that the possession of nuclear weapons rnay irnply its use or
threat of use. See the written statements presented by France and the United
Kingdom regarding the request of an advisory opinion formulated by the WHO in
resolutionWHA 46.40 (International Court of Justice, legality of the use bya State of
nuclear weapons in annedconflict: wriiten statements (originals),Septemher 1994).
1°. Decision adopted on 11 May 1995. document NPTlCONF.1995lL.6. The
Conferencewas held in New York, N.Y.,from 17April to 12 May 1995.
l. Statement Mexicoin document NPTICONF.1995/PV.18.pp. 9-10.
12. Document NPTlCONF.1995lL.6adopted without a vote by the Conferenceon
11 May 1995.
l3 Paragraph4 d).
14. , Section 1.
5. Paragraph 2.
16. Paragraph2.
17. Paragraph 3.
18. Section II.
19. Report of the Secretary General on the question of defining agression
(document A12211of 3 October 1952). cfr. in: Henkin, Louis et al. InternationalLaw,
1987. p. 681.20
The definition of aggression is contained in General Assembly resolution
3314 (XXIX): "Aggression is the use of amed force by a State against the
sovereigniy, territorial integniy or political independenΠof another State. or in any
other manner inconsistent with the Charter of the United Nations...". According to
the above-mentioned resolution. notailfoms of the use of force constiute an act of
aggression, but aggression isthe mostseriousand dangerousfomi of the illegal use
of force (preambular paragraph5 of the resolution).
21. Report of the lnternational Law Commission on the work of its forty third
session. SupplementNo. 10 (AJ46110).
22. Although the draftCode placesthe responsibilii on the individual, it has also
secunty of rnankind should not exonerate the State in question from anye peace and
responsibility, according to intemational law, for any act or omission attributed to it
(Article 5).
23 The International Law Comissionhas indicatedthat the word 'Yhreat"rneans
ais undertaken witha view to makinga State believethat force will be used against
it if certain demands are not met by that State. A threat rnay take the form of
declarations (expressions made public in wnting or orally), communications
(messages sent by the authorities of one Govemment to the authorities of another
Government, by no matter what means of transmission) and shows of force (e.g.
concentrations of troops near the frontier). See: Yearbook of the International Law
Commission,Vol. 2, Part2, p.68, documentAICN.4ISER.AI1989lAdd.l.
24. See developrnent of the concept of individual and collective self-defense in
paragraphs 54-65 infra.
25. Paragraph 1.
26. See declarationforrnulatedby Chinaon 5 April 1995,documentS11995/265.
27. See paragraph 63 infra,
28. The declarationsof the five nuclearpowers formulated on 5 and 6 Apfll 1995
are contained in documents Sl19951261,S119951262S , 119951263, SI19951264and
SI19951265.
29. Ibid. note Il supra.
30. Article 3 of Additional ProtocolII.
31. Article 39 of the Charterofthe UnitedNations,
32. Effects of nuclear war on heafih and health services, Geneva, World health
Organization, 1987; International Physicians for the Prevention of Nuclear War,
Radioactive heaven and earth, Apex Press, 1991; lnstitute of Medicine, National
1986,among rnany otherscientificstudies.ications of nuclear war, WashingtonD.C.,
33 The lnternational Court of Justice has indicated that self-defense is lirnited
oniy to a case of amed attack (Militaryand paramilitary acfivities in Nicaragua and
against Nicaragua,26 November1984). 34. See article 13 of the draft on responsibility of States being prepared by the
International Law Commission in the report of the Commission on the work of its
forty-fourth session. SupplementNo. 10(A/47/10), pp. 75-78.
35 H. Meyrowitz, Le statutdes ames nucléairesen droit international.Y.I.L. 219,
1982.
36. The Carolina Case,in Moore, Digest of lnternational Law,Vol. 2, p.409.
37. Resolutions 56(1948), 188 (1964) and 228 (1966). among others.
38. Report of the lnternational Law Commission on the work of itsfoty-fourth
session. Supplement No. 10(A/48/10),p.82.
39. Judgernent of 9April1949.
40, In this regard, it could not be accepted the argument presented by the
Government of the RussianFederationregarding the request of an advisoryopinion
formulated by the World Health Organization in resolution 46.40. by which 'it
rnentioned that reservations to Protocol Additional I show that the question of
legitimacy or non-legitimacy of the use of nuclear weapons is not regulated by
international law. (International Court of Justice,egalrty of the use by a State of
nuclear weaponsin armedconflict: wriîtenstatements (onginals), September1994).
41. Therefore, the Government of Mexico cannot agree with the conclusion
contained in the written statements of the Governments of the United Kingdom and
the United States of America regarding the request of an advisory opinion
formulated by the WHO, by which ithas affimed that there is no rule contained in
either customary international law or treaty which expressly prohiibits al1 use of
nuclear weapons (InternationalCourt of Justice. op. cit.)
42. The De Martens Clause establishes that the inhabitants and the beliigerents
remain underthe protection ofthe rule of the principles of thlaw of nations. as they
result frorn the usages established among civilized peoples frorn the laws of
hurnanity and the dictates of the public conscience, until a more cornplete code of
the laws of war has been issued.
43. Jean Pictet, cfr. in: Sandoz, Yves.Des armes interdites en droit de la guerre,
Universitéde Neuchatel, 1975,p. 69.
44. Cfr. inYves Sandoz,ibid..p. 64-65.
Note Verbale 19 June 1995 from the Embassy of Mexico, together with Written Statement of the Government of Mexico