North Atlantic Treaty

Current NATO member states

Animated map of NATO membership over time

The following twelve states signed the treaty and thus became the founding members of NATO. The following leaders signed the agreement as plenipotentiaries of their countries in Washington, D.C., on 4 April 1949:[6][7]

•  Belgium – Prime Minister and Foreign Minister Paul-Henri Spaak and Ambassador Baron Robert Silvercruys
•  Canada – Secretary of State for External Affairs Lester B. Pearson and Ambassador H. H. Wrong
•  Denmark – Foreign Minister Gustav Rasmussen and Ambassador Henrik Kauffmann
•  France – Foreign Minister Robert Schuman and Ambassador Henri Bonnet
•  Iceland – Foreign Minister Bjarni Benediktsson and Ambassador Thor Thors
•  Italy – Foreign Minister Carlo Sforza and Ambassador Alberto Tarchiani
•  Luxembourg – Foreign Minister Joseph Bech and Ambassador Hugues Le Gallais
•  Netherlands – Foreign Minister Dirk Stikker and Ambassador Eelco van Kleffens
•  Norway – Foreign Minister Halvard M. Lange and Ambassador Wilhelm von Munthe af Morgenstierne
•  Portugal – Foreign Minister José Caeiro da Mata and Ambassador Pedro Teotónio Pereira
•  United Kingdom – Foreign Secretary Ernest Bevin and Ambassador Oliver Franks
•  United States – Secretary of State Dean Acheson

The following four states joined the treaty after the 12 founding states, but before the dissolution of the Soviet Union:

The following 15 states joined the treaty after the dissolution of the Soviet Union:

No state has rescinded its membership but some dependencies of member states have not requested membership after becoming independent:

Article 1 of the treaty states that member parties "settle any international disputes in which they may be involved by peaceful means in such a manner that international peace and security, and justice, are not endangered, and to refrain in their international relations from the threat or use of force in any manner inconsistent with the purposes of the United Nations."[5]

Members seek to promote stability and well-being in the North Atlantic area through preservation of peace and security in accordance with the Charter of the United Nations.[5]

Article 2 of the treaty stipulates that "The Parties will contribute toward the further development of peaceful and friendly international relations by strengthening their free institutions, by bringing about a better understanding of the principles upon which these institutions are founded, and by promoting conditions of stability and well-being. They will seek to eliminate conflict in their international economic policies and will encourage economic collaboration between any or all of them."[8] This is sometimes referred to as the Canada Clause after Pearson pushed for its inclusion in the treaty.[9] This included proposals for a trade council, cultural program, technological sharing, and an information program. Of those, only the latter two were passed.[10][11] Nonetheless, it has been brought up by observers commenting on trade disputes between members.[12]

Article 3 of the treaty states that "In order more effectively to achieve the objectives of this Treaty, the Parties, separately and jointly, by means of continuous and effective self-help and mutual aid, will maintain and develop their individual and collective capacity to resist armed attack."[5]

Recently, this has been interpreted as the basis for the target for a 2% GDP expenditure rule,[13] which was established as a loose guideline in 2006.[14] This metric was confirmed again during the 2014 Wales summit.

It has also been used as a core concept for a mandate to strengthen member resilience: the ability to resist and recover from major disasters, failures in infrastructure, or traditional armed attack. This commitment was first accepted during the 2016 Warsaw summit, and further reiterated and clarified due to the COVID-19 pandemic in 2021.[15][16] Per NATO documents, this has been understood to include seven key areas:

• Continuity of government during a crisis
• Energy and power grid infrastructure resilience
• Immigration control
• Food and water security
• Medical emergencies
• Resilient civil communications
• Effective transportation networks[17]

Article 4 is generally considered the starting point for major NATO operations, and therefore is intended for either emergencies or situations of urgency. It officially calls for consultation over military matters when "the territorial integrity, political independence or security of any of the parties is threatened."[18] Upon its invocation, the issue is discussed in the North Atlantic Council, and can formally lead into a joint decision or action (logistic, military, or otherwise) on behalf of the Alliance.[19] It has been officially invoked seven times since the alliance's creation.[20]

Article 4 invocations

Nations	Date	Reason	Outcome
Turkey	February 2003	Iraq War.[20][21]	Operation Display Deterrence.[22]
Turkey	June 2012	The shooting down of a Turkish military jet by Syria.[20]	Operation Active Fence.[23]
Turkey	October 2012	Syrian forces shelling Turkish cities.[20]
Latvia[24]  Lithuania[25]  Poland[26]	March 2014	In response to the annexation of Crimea by the Russian Federation.	Deployment of littoral, naval, and air forces in the Black Sea by Romania, Bulgaria, and Turkey.[27] Condemnation and support for sanctions of member countries and international community.[28] Reform and medical aid to the Ukrainian government.[29] Creation of the NATO Enhanced Forward Presence.[30]
Turkey	July 2015	In response to the 2015 Suruç bombing, which it attributed to ISIS, and other security issues along its southern border.[19][31][32][33]	Main article: 2015 NATO emergency meeting Denouncement of the attack[33] and reassessment of NATO assets in Turkey.[34]
Turkey	February 2020	Increasing tensions as part of the Northwestern Syria offensive, including suspected[35] Syrian and Russian airstrikes on Turkish troops.[36][20]	Augmentation of Turkish air defences.[37][38]
Bulgaria  Czech Republic  Estonia  Latvia  Lithuania  Poland  Romania  Slovakia[39]	February 2022	2022 Russian invasion of Ukraine.[40]	See also: 2022 Brussels summit Defensive build-up,[41][42] matériel support to Ukraine,[43] and activation of the NATO Response Force.[44][45]

There have also been instances where Article 4 was not formally invoked, but instead threatened. In fact, this was viewed as one of the original intentions for Article 4: as a means to elevate issues and provide member nations a means of deterrence.[46] For example, in November 2021, the Polish foreign ministry—along with Estonia, Lithuania, and Latvia—briefly considered triggering Article 4 due to the Belarusian migrant crisis, but it was not formally requested.[47][48]

On 15 November 2022, a missile struck the territory of Poland at the village of Przewodów near the border with Ukraine.[49][50][51] The incident occurred during an attack on Ukrainian cities and energy facilities by Russia.[52][53] It was the first incident of a missile hitting NATO territory during the 2022 Russian invasion of Ukraine.[54][55] The NATO Secretary General talked with the Polish President and there was no call for an Article 4 convention,[56] although the government had been in talks to consider invoking it.[57]

The key section of the treaty is Article 5. Its commitment clause defines the casus foederis. It commits each member state to consider an armed attack against one member state, in the areas defined by Article 6, to be an armed attack against them all. Upon such attack, each member state is to assist by taking "such action as [the member state] deems necessary, including the use of armed force, to restore and maintain the security of the North Atlantic area." The article has only been invoked once, but considered in a number of other cases.

It has been invoked only once in NATO history, after the September 11 attacks on the United States in 2001.[58][59] The invocation was confirmed on 4 October 2001, when NATO determined that the attacks were indeed eligible under the terms of the North Atlantic Treaty.[60] The eight official actions taken by NATO in response to the 9/11 attacks included Operation Eagle Assist and Operation Active Endeavour, a naval operation in the Mediterranean which was designed to prevent the movement of terrorists or weapons of mass destruction, as well as enhancing the security of shipping in general. Active Endeavour began on 4 October 2001.[61]

Article 6 states that Article 5 covers only member states' territories in Europe, North America, Turkey, and islands in the Atlantic north of the Tropic of Cancer.

It was the opinion in August 1965 of the US State Department, the US Defense Department, and the legal division of NATO that an attack on the U.S. state of Hawaii would not trigger the treaty, but an attack on the other 49 would.[69] The Spanish cities of Ceuta and Melilla on the North African shore are thus not under NATO protection in spite of Moroccan claims to them. Legal experts have interpreted that other articles could cover the Spanish North African cities but this take has not been tested in practice.[70] This is also why events such as the Balyun airstrikes did not trigger Article 5, as the Turkish troops that were attacked were in Syria, not Turkey.[71]

On 16 April 2003, NATO agreed to take command of the International Security Assistance Force (ISAF) in Afghanistan, which includes troops from 42 countries. The decision came at the request of Germany and the Netherlands, the two states leading ISAF at the time of the agreement, and all nineteen NATO ambassadors approved it unanimously. The handover of control to NATO took place on 11 August, and marked the first time in NATO's history that it took charge of a mission outside of the area delineated by Article 6.[72]

In the case of any contradiction with other international obligations (with the exception of the United Nations, which by Article 7 supersedes NATO), or in military conflict of two NATO members, Article 8 comes into force. This is most important in cases should one member engage in military action against another member, upon which the offending members would be held in abeyance of the treaty and thereby NATO protection as a whole. This has not occurred yet, but there have been several militarised disputes between NATO allies that have threatened this:

NATO Militarised Interstate Conflicts

Date	Belligerents		Conflict
1958–1961, 1972–73 and 1975–76	Belgium  United Kingdom  West Germany	Iceland	Cod Wars
1974	Greece	Turkey	Turkish invasion of Cyprus
1994-1996	Canada	Spain	Turbot War
1992–Present	Greece	Turkey	The Aegean Dispute

If an intra-NATO conflict were to occur, there exist intra-NATO alliances which would be triggered instead in the instance of the abeyance. The following is a list of such active, intra-NATO military alliances.

Intra-NATO Military Alliances

Since	Members	Name
1373	Portugal  United Kingdom	Anglo-Portuguese Treaty of 1373
1940	Canada  United States	Ogdensburg Agreement
1958	United Kingdom  United States	US–UK Mutual Defence Agreement
2010	France  United Kingdom	Lancaster House Treaties
2019	Greece  United States	Mutual Defense Cooperation Agreement[73][74][75]
2021	France  Greece	Franco-Greek defence agreement
2022	Finland  United Kingdom	UK-Finland Defence Agreement[76] [77]
2023	Greece  United Kingdom	Anglo-Greek Defence Agreement[78][79]

Establishes the North Atlantic Council, and is the only NATO body that derives its authority directly from the treaty. Its primary objectives as stated in the treaty is the enforcement of Article 3 and Article 5.

Article 10 dictates the process by which other countries may join NATO, which is by unanimous agreement by current NATO members. Further, new NATO members can only consist of other European nations. In practice, this has turned into a set of action plans which an aspiring nation must follow in order to become a member, including the Membership Action Plan (MAP) mechanism[80] and Intensified Dialogue formula.[81]

Article 11 indicated the process of the initial ratification of the treaty. Each signatory nation was required to ratify the treaty through their respective constitutional processes. In order to come into force, the treaty had to be ratified by Belgium, Canada, France, Luxembourg, the Netherlands, the United Kingdom, and the United States.

Article 12 states the process by which the treaty may be amended, provided such amendments still affect the North Atlantic area and do not violate the Charter of the United Nations. In practice, this has only been used to clearly delineate which territories are under the purview of NATO.

Article 13 delimits the process by which a member leaves NATO, which simply consists of a one-year notice by the member nation to the U.S. government in its role as the treaty depositary, which then promulgates the notice to the other member nations. This has been contemplated by a number of member nations, but so far has not happened aside from withdrawals due to independence of former territories or dependencies (namely, Algeria, Malta, and Cyprus).

Otherwise, the next closest option for a member nation is to instead withdraw from NATO's military command structure, but not from NATO entirely. This happened with France in 1966, which rejoined in 2009; and with Greece in 1974, which rejoined in 1980 after the new Turkish military government ended its objections to Greek re-entry.

Article 14 notes the official languages of NATO as English and French, and that the United States government shall promulgate copies of the treaty to the other member nations.

Three official footnotes have been released to reflect the changes made since the treaty was written:[82]

Regarding Article 6:

• The definition of the territories to which Article 5 applies was revised by Article 2 of the Protocol to the North Atlantic Treaty on the accession of Greece and Turkey signed on 22 October 1951.

Regarding Article 6:

• On 16 January 1963, the North Atlantic Council noted that insofar as the former Algerian Departments of France were concerned, the relevant clauses of this Treaty had become inapplicable as from 3 July 1962.

Regarding Article 11:

• The Treaty came into force on 24 August 1949, after the deposition of the ratifications of all signatory states.