Kosovo and NATO: Selected Issues of International Law

Kosovo and NATO: Selected Issues of International Law

Order Code RL30152
CRS Report for Congress
Received through the CRS Web
Kosovo and NATO: Selected Issues of
International Law
April 28, 1999
David M. Ackerman
Legislative Attorney
American Law Division
Congressional Research Service ˜ The Library of Congress

ABSTRACT
NATO’s military intervention in Yugoslavia has raised several issues of international law.
Are there legal justifications for overriding the traditional principle of international law that
states are free to order their internal affairs as they see fit without outside interference? Do
its actions comport with the Charter of the United Nations? Is its engagement in an out-of-
area conflict that is not a response to an armed attack on one of its members permissible under
the North Atlantic Charter? This report examines those issues. It will be updated as events
warrant.

Kosovo and NATO: Selected Issues of International Law
Summary
The initiation of air attacks by NATO and its intervention in Yugoslavia have
posed a number of issues involving international law. First, questions have been
raised about whether NATO’s actions violate the principles of non-intervention and
the sovereignty of states over their internal affairs. Kosovo is not an independent
state but is a part of Yugoslavia; and the conflict between the Serbs and the KLA and
the maltreatment of ethnic Albanians, therefore, had previously been an internal matter
rather than an international one. But international law has traditionally afforded states
complete sovereignty over their internal affairs and has barred intervention into those
affairs by other states. Thus, one issue is whether there are other principles under
international law that justify overriding the traditional principles of non-intervention
and sovereignty.
Another issue concerns whether NATO’s initiative has been authorized by the
U.N. Security Council or must find legal justification elsewhere. The Security
Council has had the Kosovo situation under review for some time and addressed the
matter in several resolutions last year. But it has not authorized its members or any
regional organization to take military action. As a consequence, questions have been
raised about whether NATO’s intervention is consistent with the UN Charter.
A third issue concerns whether NATO’s actions fall within the authority
conferred by the North Atlantic Treaty. NATO was created primarily as a defensive
alliance to protect the territory of its members from armed attack. But in this instance
none of its members has been subjected to attack or the threat of attack. Moreover,
NATO is engaging in a mission outside the territory of any of its members. Thus,
questions have been raised about its authority under the North Atlantic Treaty to
engage in an out-of-area mission that is not a response to an attack on one of its
members.
This report examines these issues and concludes that the implications of NATO’s
intervention in Yugoslavia for international law depend to a great degree on
assumptions regarding the current state of international law. If, for instance, one
assumes that the principles of the sovereignty of states over their internal affairs and
non-intervention remain absolute pillars of international law, NATO’s actions are
clearly violative. Similarly, if one assumes that the U.N. Charter has made the use of
force by states unlawful except as authorized by the Security Council or in self-
defense against armed attack, NATO’s actions, again, appear violative, even though
they appear consistent with the North Atlantic Treaty. But absent these assumptions,
a number of different conclusions emerge. NATO’s actions, for instance, may find
legal justification in the emerging doctrine of humanitarian intervention as well as in
the customary international law of self-defense. Both of these issues remain subjects
for debate in international law. NATO’s actions, thus, both reflect and promote
particular aspects of this ongoing debate about humanitarian intervention and self-
defense.
This report will be revised and updated as events warrant.

Contents
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
(1) Principle of Non-intervention . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
(2) United Nations Charter and NATO’s Intervention . . . . . . . . . . . . 1
(3) North Atlantic Treaty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Principle of Non-Intervention . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
The United Nations and NATO’s Air Strikes . . . . . . . . . . . . . . . . . . . . . . . 6
NATO’s Legal Authority . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Kosovo and NATO: Selected Issues of
International Law
Introduction
On March 24, 1999, the North Atlantic Treaty Organization (NATO) initiated
air strikes against the Federal Republic of Yugoslavia (Serbia-Montenegro) in an
attempt to convince the Yugoslav government to cease its ethnic cleansing in Kosovo
and to enter into a political settlement for that region. In response the Yugoslav
army, Serbian police forces, and paramilitary groups accelerated and expanded their
attacks on the Kosovo Liberation Army (KLA) and ethnic Albanian civilians in
Kosovo. Those actions precipitated a flood of Kosovar refugees pouring into
Macedonia, Albania, and Montenegro.
The initiation of air attacks by NATO and its involvement in armed conflict in
Yugoslavia has raised a number of issues involving international law, including the
following:

(1) Principle of Non-intervention. Kosovo is not an independent state but is
a part of Yugoslavia; and the conflict between the Serbs and the KLA and the
maltreatment of ethnic Albanians, therefore, had previously been an internal conflict
rather than an international one. As a consequence, some have questioned whether
military intervention by outside powers in that conflict violates the traditional principle
of international law barring intervention by one state or group of states in the internal
affairs of another state.
(2) United Nations Charter and NATO’s Intervention. The United Nations
Security Council has had the Kosovo situation under review for some time and has
addressed the matter in several resolutions. But it has not authorized its members or
any regional organization to take military action. Moreover, the U.N. Charter is
interpreted by some as prohibiting the use of force except in limited circumstances.
As a consequence, questions have been raised about whether NATO’s intervention
is consistent with the UN Charter.
(3) North Atlantic Treaty. NATO was created primarily as a defensive alliance
to protect the territory of its members from armed attack. But in this instance none
of its members has been subjected to attack or the threat of attack. Moreover, NATO
is engaging in a mission outside the territory of any of its members. Thus, questions
have been raised about its authority under the North Atlantic Treaty to engage in an
out-of-area mission that is not a response to an attack on one of its members.

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To aid the House and the Senate in their examination of the various legal
components of U.S. involvement in NATO’s actions, this rep
1
ort explores these issues
of international law. It will be revised as events warrant.
Principle of Non-Intervention
International law has traditionally dealt with how states in the international arena
conduct themselves in their relationships with one another. Its development has been
premised on the notions that all states, whatever their size and relative power, are
equal and that each is sovereign within its own territory. As a consequence,
international law has made non-intervention in the internal affairs of other states a
central obligation. Only in recent decades has international law begun to address how
states conduct themselves in their internal affairs, i.e., how they treat their own
nationals.
The Charter of the United Nations itself recognizes this legal heritage. The
Charter states one of the UN’s purposes to be
[t]o develop friendly relations among Nations based on respect for the principle of
equal rights and self-determination of peoples ...2
and asserts that
[n]othing contained in the present Charter shall authorize the United Nations to
intervene in matters which are essentially within the domestic jurisdiction of any
State ....3
Moreover, the U.N. Charter commits its members to
settle their international disputes by peaceful means in such a manner that
international peace and security, and justice, are not endangered4
and provides that
[a]ll Members shall refrain in their international relations from the threat or use of
force against the territorial integrity or political independence of any State ....5
In the Declaration on Principles of International Law Concerning Friendly Relations
and Cooperation Among States in Accordance with the Charter of the United
As
1
of this date, the Committee on International Relations of the House of Representatives has
reported both H.J.Res. 44 and H.Con.Res. 82 with a recommendation that they be rejected by
the House. Senator McCain has introduced S.J.Res. 20 in the Senate.
U.N. Charter, Art. 1(2).
2
Id.
3
Art. 2(7).
Id.
4
Art. 1(2).
Id.
5
Art. 2(4).

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Nations, the General Assembly in 1970 adopted by consensus the followin
6
g
elaboration of these principles of the Charter:
All States enjoy sovereign equality ... (which) includes the following elements:
(a) ...;
(b) ...;
(c) ...;
(d) The territorial integrity and political independence of each State are inviolable;
(e) Each State has the right freely to choose and develop its political, social,
economic and cultural systems.
....
No State or group of States has the right to intervene, directly or indirectly, for any
reason whatsoever, in the internal or external affairs of any other State.
Consequently, armed intervention and all other forms of interference or attempted
threats against the personality of the State or against its political, economic and
cultural elements, are in violation of international law.
....
Every State has an inalienable right to choose its political, economic, social and
cultural systems, without interference in any form by another State.
International law, it is clear, has traditionally deemed each state to have the sovereign
right to order its internal affairs as it sees fit, free from outside interference.
Viewed through this prism, NATO’s actions seem clearly violative of customary
international law and of the U.N. Charter. However, three developments in the past
half-century arguably allow this principle of non-intervention to be overridden in some
circumstances. First, the U.N. Charter itself states that the principle of non-
intervention in the internal affairs of states “shall not prejudice the application of
enforcement measures under Chapter VII.” That Chapter authorizes the Securit
7
y
Council to “determine the existence of any threat to the peace, breach of the peace,
or act of aggression” and to make recommendations and other actions to maintain or
restore international peace and security.” Similarly, the General Assembly resolution
noted above expanding on the meaning of the Charter with respect to friendly
relations among states explicitly states that “[n]othing in the foregoing paragraphs
shall be construed as affecting the relevant provisions of the Charter relating to the
maintenance of international peace and security.” Thus, international law as reflected
in the Charter appears to permit intervention in the internal affairs of states under the
auspices of the UN to the extent that the Security Council determines that those
affairs threaten international peace and security. That, however, has not happened in
the current situation (see next section).
Secondly, the U.N. Charter also recognizes in Article 51 the “inherent right of
individual or collective self-defense if an armed attack occurs against a Member of the
United Nations, until the Security Council has taken measures necessary to maintain
G.A. Res. 2625 (XXIV) (1970).
6
7U.N. Charter, Art. 2(7). Chapter VII authorizes the Security Council to “determine the
existence of any threat to the peace, breach of the peace, or act of aggression” and to take
measures “to maintain or restore international peace and security.”

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international peace and security.”8 Thus, the Charter clearly allows a state or group
of states to intervene in the internal affairs of another state if necessary to defend
themselves from an armed attack by that state. Again, that has not happened in the
current situation; at least in Kosovo, Yugoslavia has attacked only its own nationals,
not another state. However, it should be noted that there is an ongoing debate
concerning whether the limitation of self-defense in Article 51 to responses to armed
attack comprises the whole of what international law now allows. Historically, the
right of self-defense embodied in customary international law was not limited to a
state’s response to an armed attack but covered various other forms of self-help
involving the use of force but falling short of war — retorsion, reprisals,
9
10
embargoes, boycotts, temporary occupations of foreign territory, pacific blockades,
etc. Moreover, notwithstanding the prohibition on the use of force in Article 2(4) of
the UN Charter, numerous states have continued to use these forms of self-help,
including military force, since the adoption of the U.N. Charter. Thus, some contend
that Article 51's reference to the “inherent right of ... self-defense” and the continued
use of forcible forms of self-help by states shows that the U.N. Charter preserves and
allows all the forms of self-defense that had previously been sanctioned by customary
international law. Others contend that the Article 51 limitation supersedes what had
been customary international law in these matters, that the limitation is now binding
on states, and that the continued use of force by states apart from armed attacks is in
violation of the Charter. Thus, the use of self-defense as a justification fo
11
r
overriding the principles of sovereignty and non-intervention seems most tenable
under international law when it is a response to an armed attack, as permitted by
Article 51 of the U.N. Charter. But its legitimacy may also be argued, although with
less certainty, in situations not involving a response to an armed attack, such as that
in Yugoslavia. The argument that NATO’s actions in Yugoslavia constitute a form
of anticipatory collective self-defense has been used with respect to NATO’s actions
in Yugoslavia.12
Id.
8
Chapter VII, Art. 51.
9Retorsion is the commission of an unfriendly but legal act in response to a prior, equally
unfriendly legal or illegal act by another state. Frequently, it takes the form of tit for tat.
State A will impose travel restrictions on the diplomats of state B; state B will respond in kind
with respect to the diplomats of state A. State A will deny visas to certain officials of state
B; state B will respond in kind. But it doesn’t have to be a response in kind. When Iran
seized the U.S. embassy and most of its staff in 1979, for instance, the U.S. responded not by
seizing Iranian diplomats but by such measures as freezing Iranian assets in the U.S.,
invalidating all visas issued to Iranians, and embargoing exports to Iran. See, generally, von
Glahn, Gerhard, Law Among Nations (1992), pp. 633-640.
10Reprisals are illegal acts undertaken in response to another state’s illegal acts — military
incursions into the territory of the offending state, bombardment of its territory, and
nonperformance of treaty obligations, for example. See von Glahn, supra n. 6, pp. 640-644.
See
11
von Glahn, supra, p. 646, and Simma, Bruno, The Charter of the United Nations: A
Commentary (1994), pp. 661-678.
1 See
2
, e.g., Hearing Before the Committee on International Relations of the House of
Representatives: United States Policy on Kosovo (April 21, 1999) (statement of Secretary
of State Madeleine K. Albright).

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A final legal justification for overriding the principle of non-intervention emerges
from the modern development of the international law of human rights. On the basis
of the tenets of human rights recognized by the tribunals at Nuremberg and Tokyo
after World War II and more recently in the charters of the tribunals for the former
Yugoslavia and Rwanda; the provisions of the U.N. Charter obligating its members
to promote and encourage respect for human rights ; the formulation and adoption
13
by the U.N. General Assembly of the Universal Declaration of Human Rights in
1948 ;
14 and the widespread adoption of numerous treaties and conventions concerning
human rights such as the Geneva Conventions, the International Covenant on Civil
15
and Political Rights, the Genoci
16
de Convention,17 the Convention on the Elimination
of Racial Discrimination, and the Torture Conven
18
tion,19 it is contended by some that
states are no longer free under international law to mistreat their own nationals but
are obligated to respect their fundamental human rights. A corollary of this
development is that it may now be lawful for another state or states or the
international community to intervene in the internal affairs of a given state in order to
rectify serious violations of human rights, i.e., to intervene for essentially humanitarian
reasons in order to protect the nationals of that state from depredations by their own
government. As defined by one author, humanitarian intervention means
the threat or use of force by a state, group of states, or international organization
primarily for the purpose of protecting the nationals of the target state from
widespread deprivations of internationally recognized human rights, whether or not
the intervention is authorized by the target state or the international community.20
This doctrine is not yet fully developed in international law. But humanitarian
considerations have been repeatedly invoked to justify NATO’s actions in
Yugoslavia ;
21 and the doctrine of humanitarian intervention may, at least in some
form, provide a possible justification under international law for NATO’s intervention
in Kosovo and Yugoslavia.
U.N. Charter, Articles 1(3), 13(1)(b), and 55(c).
13
U.N. Document A/811 (1948).
14
6 UST 3114, 3217, 3316, and 3516 (1956).
15
TIAS ___ (1992).
16
TIAS ___ (1989).
17
TIAS ___ (1994).
18
TIAS ___ (1994).
19
Murphy,
20
Sean D., Humanitarian Intervention: The United Nations in an Evolving World
Order (1996), at 3-4.
See,
21
e.g., Hearing Before the Committee on International Relations, supra n. 9 (statement
of the Secretary of State); White House Office of the Press Secretary, Text of a Letter from
the President to the Speaker of the House of Representatives and the President Pro Tempore
of the Senate (March 26, 1999); and NATO Press Release, Statement by the North Atlantic
Council on Kosovo (Jan. 30, 1999).

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The United Nations and NATO’s Air Strikes
As noted above, the UN Charter appears to authorize intervention in the internal
affairs of states in certain circumstances, notwithstanding the traditional pillars of
international law of state sovereignty and non-intervention. Under Chapter VI of the
Charter, the Security Council may
investigate any dispute, or any situation which might lead to international friction
or give rise to a dispute, in order to determine whether the continuance of the
dispute or situation is likely to endanger the maintenance of international peace and
security.
In such situations the Security Council may also make recommendations for resolving
the dispute or situation. Chapter VII of the UN Charter, in turn, authorizes the
Security Council to “determine the existence of any threat to the peace, breach of the
peace, or act of aggression” and not only to make recommendations but also to take
action “to maintain or restore international peace and security.” Such action can
include the use of armed force as well as economic and diplomatic measures. Neither
Chapter VI nor Chapter VII is explicitly limited to disputes between states.
In addition, Chapter VIII of the UN Charter specifically permits regional entities
to deal with “matters relating to the maintenance of international peace and security
as are appropriate for regional action, provided that such arrangements or agencies
and their activities are consistent with the Purposes and Principles of the United
Nations.” Chapter VIII further provides that such entities may seek the “pacific
settlement of local disputes” and authorizes the Security Council to use “regional
arrangements or agencies for enforcement action under its authority,” where
appropriate. But it prohibits enforcement action by such regional entities “without the
authorization of the Security Council ....”
The legal issue is whether NATO’s military intervention in Yugoslavia is
consistent with these provisions or must seek justification under international law
elsewhere. Thus, it deserves notice that the Security Council has repeatedly taken
action with respect to Kosovo. After large-scale violence broke out in late February,
1998, the Security Council in Resolution 1160 took
22
cognizance of developments
in Kosovo under Chapter VII of the Charter and undertook a number of actions to try
to bring about a peaceful resolution of the situation. Among other measures, the
Security Council imposed an arms embargo on Yugoslavia (including Kosovo), called
for negotiations between governmental authorities in Yugoslavia and the Kosovar
Albanian leadership, approved “a substantially greater degree of autonomy and
meaningful self-determination” for Kosovo, and endorsed the efforts of the Contact
Group and the Organization for Security and Cooperation in Europe (OSCE) t
23
o
S/Res/1160 (March 31, 1998).
22
The
23
Contact Group is composed of France, Germany, Italy, Russia, Great Britain, and the
United States.

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resolve the situation peacefully. Subsequently, in Resolution 1199 the Securit
24
y
Council in September, 1998, took note of the escalating conflict in Kosovo and the
increasing numbers of refugees and displaced persons, specifically identified the
situation as constituting a threat to peace and security in the region, called for a cease-
fire and renewed negotiations, and endorsed the efforts of the European Community
Monitoring Mission and the Kosovo Diplomatic Observer Mission in Kosovo.
Finally, in October, 1998, the Security Council in Resolution 1203 endorsed the
agreements permitting the OSCE to monitor compliance on the ground in Kosovo
with its previous resolutions and NATO to do so from the air, reiterated that the
situation constituted a continuing threat to peace and security in the region, called on
Yugoslavia to honor its commitment to negotiate a political settlement of the conflict,
reaffirmed the right of refugees and displaced persons to return to their homes in
safety, and reiterated its previous endorsement of enhanced autonomy for Kosovo.
Although the Resolution made no mention of the threat of NATO air strikes, the
Council was undoubtedly aware that NATO on October 13 had threatened air strikes
if Yugoslavia continued to obstruct compliance with the UN’s resolutions and
negotiations toward a political settlement.
All of these resolutions, it is apparent, explicitly contemplated the active
involvement of regional organizations in Europe in trying to resolve the situation in
Kosovo. But none of the resolutions specifically authorized the use of force against
Yugoslavia either by Member States or by regional organizations such as NATO. The
absence of such authorization stands in contrast to past resolutions authorizing the use
of force by regional organizations in Bosnia-Herzegovina, where the authorization has
been explicit.25 Thus, although it might be argued that the objectives of NATO’s
actions are “consistent with the Principles and Purposes of the United Nations”
(Chapter VIII), it seems more difficult to conclude that NATO’s air strikes against
Yugoslavia meet the requirement of Article VIII that enforcement action by regional
agencies not be undertaken without the authorization of the Security Council.
Similarly, it seems doubtful that NATO’s air strikes fall within the Charter’s
provisions concerning self-defense. As noted above, Article 51 of the Charter
provides that
[n]othing in the present Charter shall impair the inherent right of individual or
collective self-defence if an armed attack occurs against a Member of the United
Nations, until the Security Council has taken measures necessary to maintain
international peace and security.
S/Res/1199 (September 23, 1998).
24
See,
25
e.g. S/Res/816 (1993) authorizing Member States “acting nationally or through regional
organizations” to use “all necessary measures” to enforce a no-fly zone over Bosnia-
Herzegovina; S/Res/836 (1993) authorizing Member States “acting nationally or through
regional organizations” to take “all necessary measures through the use of air power” to
protect six safe haven areas for Bosnian Muslims; S/Res/ 1031 (1995) authorizing Member
States “acting through or in cooperation with” NATO to establish a multinational
implementation force to assist in the implementation of the Dayton Agreement; and
S/Res/1088 (1996) authorizing Member States “acting through or in cooperation with” NATO
to establish a smaller multinational stabilization force to enforce compliance with the Peace
Agreement.

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Thus, if Yugoslavia had engaged in an armed attack on a member state of the U.N.
(which includes all of the member states of NATO) rather than on its own citizens in
Kosovo, NATO’s air strikes might find legal justification in Article 51. But in this
instance there has been no armed attack on a member of the United Nations as
required by Article 51. Instead, Yugoslavia’s use of armed force has been against its
own nationals.
Thus, NATO’s military initiative in Yugoslavia does not appear to find legal
refuge in the provisions of the UN Charter but must look elsewhere. As noted in the
foregoing section, at least two possibilities exist — (1) the doctrine of humanitarian
intervention, and (2) the customary law of self-defense. Humanitarian intervention
involves forcible intervention by other states to protect the nationals of a country from
large-scale depredations by their own government. That seems to be exactly what
NATO is doing, at least in part — protecting the Albanian Kosovars from ethnic
cleansing by the Belgrade government. But the doctrine of humanitarian intervention
is of relatively recent vintage in international law and several controversies still attend
its invocation. One key issue of contention relevant to the current situation is whether
humanitarian intervention is permissible outside the auspices of the U.N. Some
commentators argue that self-initiated humanitarian intervention by a state or group
of states cannot be reconciled with the restraints on the unilateral use of force
embodied in the U.N. Charter, while others contend that those restraints are
sufficiently flexible to allow unilateral interventions in some circumstances. Closely
26
related arguments are that recognition of a right of unilateral humanitarian
intervention under international law, uncontrolled by the Security Council, would
inevitably lead to abuse by unscrupulous states and that it is not possible to develop
criteria for such interventions that would obtain universal adherence. Thus, NATO’s
27
intervention in Yugoslavia may find legal support in international law in the emerging
doctrine of humanitarian intervention, but its actions appear both to reflect and to
promote a particular view of humanitarian intervention. Its actions affirm, first, that
intervention by a regional group of states in the internal affairs of another state is
permissible to remedy gross violations of human rights and, secondly, that such
intervention is lawful even absent Security Council authorization or, at least, when
the Security Council is unable to act.
Another possible legal contention is that the member states of NATO are
engaging in an exercise of collective self-defense permitted by international law. The
dangers posed to European peace and security by Yugoslavia’s actions in Kosovo
and, before then, in Slovenia, Croatia, and Bosnia-Herzegovina, have been frequently
cited in support of NATO’s actions. For instance, President Clinton stated as follows
in his March 26, 1999, letter to the Speaker of the House and the President pro tem
of the Senate:
The continued repression by the FRY military and security police forces
constitutes a threat to regional security, particularly to Albania and Macedonia
26See the discussion in Murphy, supra, at 356-387, and Gordon, Ruth, “Humanitarian
Intervention by the United Nations: Iraq, Somalia, and Haiti,” 31 Texas International Law
Journal 43 (1996).
Id.
27

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and, potentially, to Greece and to Turkey. Tens of thousands of others have been
displaced from their homes, and many of them have fled to the neighboring
countries of Bosnia, Albania, and Macedonia. These actions are the result of
policies pursued by President Milosevic, who started the wars in Bosnia and
Croatia, and moved against Slovenia in the last decade.28
Secretary of State Albright reiterated this justification in recent testimony before the
House Committee on International Relations:
Kosovo is a small part of a region with large historic importance and a vital role
to play in Europe’s future. The region is a crossroads where the Western and
Orthodox branches of Christianity and the Islamic world meet. It is where World
War I began, major battles of World War II were fought, and the worst fighting
since Hitler’s surrender occurred in this decade. Its stability directly affects the
security of our Greek and Turkish allies to the south, and our new allies Hungary,
Poland and the Czech Republic to the north. Kosovo itself is surrounded by small
and struggling democracies that are being overwhelmed by the flood of refugees
Milosevic’s ruthless policies are creating. Today, this region is the critical missing
piece in the puzzle of a Europe whole and free. That vision of a united and
democratic Europe is critical to our own security. And it cannot be fulfilled if this
part of the continent remains wracked by conflict.29
Again, however, NATO’s actions appear to reflect and promote a particular view of
what kind of collective self-defense remains lawful. Its actions suggest that Article
51 of the U.N. Charter is not to be read as limiting customary international law
regarding self-defense; that the unilateral use of force remains viable, at least when the
Security Council is unable to act; and that force may be used in anticipation of the
development of a serious threat to regional peace and security to forestall that
development.
NATO’s Legal Authority
A further question in the current situation concerns whether NATO’s
intervention in Yugoslavia is consistent with the North Atlantic Treaty. That Treaty
30
was adopted in 1949 essentially as a collective defense pact to protect against Soviet
aggression. Article 5 stated the Treaty’s essential obligation: An armed attack
against one member state was to be considered an armed attack against all of the
member states, and every state was to “assist the Party or Parties so attacked by
taking forthwith, individually and in concert with the other Parties, such action as it
deems necessary, including the use of armed force, to restore and maintain the
security of the North Atlantic area.” Article 11, in turn, provided that this and the
other provisions of the Treaty were to be carried out by the member states “in
accordance with their respective constitutional processes.”
Letter
28
from President Clinton to the Speaker of the House and the President pro tempore of
the Senate (March 26, 1999).
29Hearing Before the Committee on International Relations, supra n. 18 (statement of
Secretary of State Albright).
63 Stat. 2241 (1949).
30

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The pact, thus, essentially protected the territories of the member states from
outside attack. In the current situation, of course, NATO’s initiative has not been
triggered by an outside attack on any of its member states and concerns an area
outside the territory of any of them. As a consequence, it seems clear that the
initiative cannot be said to fall under the rubric of Article 5.
NATO’s initiative in Yugoslavia may find legal justification, however, in Article
4 of the Treaty, as elaborated by NATO’s post-Cold War New Strategic Concept.
Article 4 provides as follows:
The Parties will consult together whenever, in the opinion of any of them, the
territorial integrity, political independence or security of any of the Parties is
threatened.
Thus, Article 4 does not commit the member states of NATO to take any particular
action, but it does allow them to consult together with respect to perceived threats to
their security apart from an armed attack. Moreover, it does not limit such perceived
threats to those involving the territorial area of the member states, nor does it appear
to place any limits on the kind of responses the member states might make to such
perceived threats.
Secretary of State Dean Acheson articulated a broad scope for Article IV when
the North Atlantic Treaty was being debated in 1949. According to the official notes
of the State Department on a press conference held on March 18, 1949, Secretary
31
Acheson first stated that the scope of issues subject to discussion under Article IV is
“broader than what fell within the scope of ... Article V.” Then,
asked if there was no provision for anything except consultation, except armed
attack on one of the signatories, the Secretary replied that there were Article I
[settlement of disputes by peaceful means], II [promotion of democracy and
stability], III [development of defense resources to deter attack], and IV. Asked
if there were no limiting clause, the Secretary stated that there was no limiting
clause. A correspondent asked if the area of the Treaty was specified but was not
necessarily limited as to what the Parties might do after they might consult,
considering the fact that an attack to security might originate outside of the
geographical limits of the Treaty .... Asked if the Treaty stipulated that if armed
attack should originate outside of the area no action might be taken, the Secretary
replied in the negative.
In 1990 NATO developed and adopted a “New Strategic Concept” to guide its
operations in the post-Cold War era. That document noted that “[t]he securit
32
y
challenges and risks which NATO faces are different in nature from what they were
in the past” and that NATO needed to adopt “a broad approach to security”:
31U.S. State Department Document, Press Conference of Secretary of State Dean Acheson
(March 18, 1949). No verbatim transcript was made.
The
32
New Strategic Concept was approved by the Heads of State and Government
participating in the meeting of the North Atlantic Council in Rome on November 7-8, 1990.

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Risks to Allied security are less likely to result from calculated aggression against
the territory of the Allies, but rather from the adverse consequences of instabilities
that may arise from the serious economic, social and political difficulties, including
ethnic rivalries and territorial disputes, which are faced by many countries in
central and eastern Europe.
The document further noted that one of the “fundamental security tasks” performed
by NATO was
[t]o serve, as provided for in Article 4 of the North Atlantic Treaty, as a
transatlantic forum for Allied consultations on any issues that affect their vital
interests, including possible developments posing risks for members’ security, and
for appropriate co-ordination of their efforts in fields of common concern.
The document further claimed that this statement made no change in the rights and
obligations of the member states as originally provided in the North Atlantic Treaty.
This expansive understanding of NATO’s functions was reportedly reaffirmed in a
revision of the New Strategic Concept adopted by NATO’s member states at the 50th
anniversary celebration in Washington on April 24, 1999.33
Although the U.S. Senate did not explicitly address the issue of out-of-area
missions for NATO when it first gave its consent to the North Atlantic Treaty in
1949, it did do so in its recent resolution of advice and consent to the accession of
Poland, Hungary, and the Czech Republic to the Treaty. In a declaration attached to
the resolution of advice and consent it adopted on April 30, 1998, the Senate stated:
(i) in order for NATO to serve the security interests of the United States, the
core purpose of NATO must continue to be the collective defense of the territory
of all NATO members; and
(ii) NATO may also, pursuant to Article 4 of the North Atlantic Treaty, on
a case-by-case basis, engage in other missions when there is a consensus among
its members that there is a threat to the security and interests of NATO members.34
Conclusion
The implications of NATO’s intervention in Yugoslavia for international law
depend to a great degree on assumptions regarding the current state of international
law. If, for instance, one assumes that the principles of the sovereignty of states over
their internal affairs and non-intervention remain absolute pillars of international law,
NATO’s actions are clearly violative. Similarly, if one assumes that the U.N. Charter
has made the use of force by states unlawful except as authorized by the Security
Council or in self-defense against armed attack, NATO’s actions, again, appear
violative, notwithstanding that though those actions seem consistent with the North
Atlantic Treaty as elaborated by the New Strategic Concept.
See New York Times
33
(April 25, 1999), p. 12).
3 144
4
CONG.REC. S4219 (daily ed. May 4, 1998) (text of resolution of ratification to the
Protocols to the North Atlantic Treaty of 1949 on the accession of Poland, Hungary, and the
Czech Republic).

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But from a perspective that assumes NATO’s actions in Yugoslavia are intended
to accord with international law, several different conclusions regarding the
international legal implications of those actions may be drawn. Again, from this
perspective its actions appear to be consistent with the North Atlantic Treaty as
elaborated by the New Strategic Concept. But its intervention in Yugoslavia clearly
asserts the proposition that the principles of non-intervention and the sovereignty of
individual states over their internal affairs are not absolute principles of international
law but are now subject to limitation by the international community, at least in
certain circumstances. Its actions further suggest that lawful limitations on the
principles of non-intervention and the sovereignty of states can be derived from the
still-developing doctrine of humanitarian intervention and from the customary law of
self-defense. With respect to emerging doctrine of humanitarian intervention, its
actions reflect and promote the view that unilateral intervention for humanitarian
purposes is permissible apart from authorization by the Security Council, at least
where the Security Council is unable to act. With respect to self-defense, its actions
reflect and promote the view that Article 51 of the U.N. Charter does not prohibit the
unilateral use of force in situations other than defense against armed attack, that the
use of force by states for reasons of collective self-defense is lawful apart from
authorization by the Security Council, at least where the Security Council is unable
to act; and that the unilateral use of force by states is permissible under international
law as a matter of anticipatory self-defense to prevent the development of a serious
threat to regional peace and security, at least where the Security Council is unable to
act. From this perspective, in other words, NATO’s actions both reflect and shape
international law.