A defense pact (or defence pact in Commonwealth spelling) is a type of

treaty A treaty is a formal, legally binding written agreement between actors in international law. It is usually made by and between sovereign states, but can include international organizations An international organization or international o ...

military alliance A military alliance is a formal Alliance, agreement between nations concerning national security. Nations in a military alliance agree to active participation and contribution to the defense of others in the alliance in the event of a crisis. ...

in which the signatories promise to support each other militarily and to defend each other.Volker Krause, J. David Singer "Minor Powers, Alliances, And Armed Conflict: Some Preliminary Patterns", in "Small States and Alliances", 2001, pp 15–23, (Print) (Online

/ref> In general, the signatories point out the threats in the treaty and concretely prepare to respond to it together.Fulvio Attinà "State aggregation in defense pacts: systemic explanations", Jean Monnet Working Papers, University of Catania, nr. 56, November 2004, ISSN 2281-902

/ref>

Current treaties

China

* 1961: Sino-North Korean Mutual Aid and Cooperation Friendship Treaty – mutual defense treaty with

North Korea North Korea, officially the Democratic People's Republic of Korea (DPRK), is a country in East Asia. It constitutes the northern half of the Korea, Korean Peninsula and shares borders with China and Russia to the north, at the Yalu River, Y ...

Russia

* 1992: Collective Security Treaty – established the

Collective Security Treaty Organization The Collective Security Treaty Organization (CSTO) is an intergovernmental military alliance in Eurasia consisting of six post-Soviet states The post-Soviet states, also known as the former Soviet Union (FSU), the former Soviet Republics ...

that also includes

Armenia Armenia (), , group=pron officially the Republic of Armenia,, is a landlocked country in the Armenian Highlands of Western Asia.The UNbr>classification of world regions places Armenia in Western Asia; the CIA World Factbook , , and ''Ox ...

Belarus Belarus,, , ; alternatively and formerly known as Byelorussia (from Russian ). officially the Republic of Belarus,; rus, Республика Беларусь, Respublika Belarus. is a landlocked country in Eastern Europe. It is bordered by R ...

Kazakhstan Kazakhstan, officially the Republic of Kazakhstan, is a transcontinental country located mainly in Central Asia and partly in Eastern Europe. It borders Russia to the north and west, China to the east, Kyrgyzstan to the southeast, Uzbeki ...

Kyrgyzstan Kyrgyzstan,, pronounced or the Kyrgyz Republic, is a landlocked country in Central Asia. Kyrgyzstan is bordered by Kazakhstan to the north, Uzbekistan to the west, Tajikistan to the south, and the People's Republic of China to the east. ...

, and

Tajikistan Tajikistan (, ; tg, Тоҷикистон, Tojikiston; russian: Таджикистан, Tadzhikistan), officially the Republic of Tajikistan ( tg, Ҷумҳурии Тоҷикистон, Jumhurii Tojikiston), is a landlocked country in Centr ...

United Kingdom

* 1949:

North Atlantic Treaty The North Atlantic Treaty, also referred to as the Washington Treaty, is the treaty that forms the legal basis of, and is implemented by, the North Atlantic Treaty Organization (NATO). The treaty was signed in Washington, D.C., on 4 April 194 ...

(Treaty of Washington) – establishes

NATO The North Atlantic Treaty Organization (NATO, ; french: Organisation du traité de l'Atlantique nord, ), also called the North Atlantic Alliance, is an intergovernmental military alliance between 30 member states – 28 European and two No ...

mutual defense organization * 1958:

US–UK Mutual Defence Agreement The US–UK Mutual Defense Agreement, or 1958 UK–US Mutual Defence Agreement, is a bilateral treaty between the United States and the United Kingdom on nuclear weapons co-operation. The treaty's full name is Agreement between the Government ...

* 1971:

Five Power Defence Arrangements The Five Power Defence Arrangements (FPDA) are a series of bilateral defence relationships established by a series of multi-lateral agreements between Australia, Malaysia, New Zealand, Singapore, and the United Kingdom, all of which are Commonwe ...

* 2021:

AUKUS AUKUS (, ) is a trilateral security pact between Australia, the United Kingdom, and the United States, announced on 15 September 2021 for the Indo-Pacific region. Under the pact, the US and the UK will help Australia to acquire nuclear-powered ...

- mutual defense alliance between

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and North ...

, and the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

United States

* 1947:

Inter-American Treaty of Reciprocal Assistance The Inter-American Treaty of Reciprocal Assistance (commonly known as the Rio Treaty, the Rio Pact, the Treaty of Reciprocal Assistance, or by the Spanish-language acronym TIAR from ''Tratado Interamericano de Asistencia Recíproca'') is an agree ...

(Rio Treaty) – establishes

Western Hemisphere The Western Hemisphere is the half of the planet Earth that lies west of the prime meridian (which crosses Greenwich, London, United Kingdom) and east of the antimeridian. The other half is called the Eastern Hemisphere. Politically, the term We ...

mutual defense organization * 1949:

(Treaty of Washington) – establishes

mutual defense organization * 1951: Mutual Defense Treaty Between the United States and the Philippines – mutual defense treaty with the

Philippines The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republika kan Filipinas * ceb, Republika sa Pilipinas * cbk, República de Filipinas * hil, Republ ...

* 1951:

ANZUS The Australia, New Zealand, United States Security Treaty (ANZUS or ANZUS Treaty) is a 1951 non-binding collective security agreement between Australia and New Zealand and, separately, Australia and the United States, to co-operate on military ...

– mutual defense alliance between

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

, and the

* 1953:

Mutual Defense Treaty Between the United States and the Republic of Korea Mutual may refer to: *Mutual organization, where as customers derive a right to profits and votes *Mutual information, the intersection of multiple information sets *Mutual insurance, where policyholders have certain "ownership" rights in the orga ...

– mutual defense treaty with

South Korea South Korea, officially the Republic of Korea (ROK), is a country in East Asia, constituting the southern part of the Korea, Korean Peninsula and sharing a Korean Demilitarized Zone, land border with North Korea. Its western border is formed ...

* 1958:

. * 1960:

Treaty of Mutual Cooperation and Security Between the United States and Japan The , more commonly known as the U.S.-Japan Security Treaty in English and as the or just in Japanese, is a treaty that permits the presence of U.S. military bases on Japanese soil, and commits the two nations to defend each other if one or th ...

– mutual defense treaty with

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

* 2021:

– mutual defense alliance between

, and the

Historical treaties

Russia

* 1881:

League of the Three Emperors The League of the Three Emperors or Union of the Three Emperors (german: Dreikaiserbund) was an alliance between the German, Russian and Austro-Hungarian Empires, from 1873 to 1887. Chancellor Otto von Bismarck took full charge of German foreign po ...

– between the

German Empire The German Empire (),Herbert Tuttle wrote in September 1881 that the term "Reich" does not literally connote an empire as has been commonly assumed by English-speaking people. The term literally denotes an empire – particularly a hereditary ...

Austria-Hungary Austria-Hungary, often referred to as the Austro-Hungarian Empire,, the Dual Monarchy, or Austria, was a constitutional monarchy and great power in Central Europe between 1867 and 1918. It was formed with the Austro-Hungarian Compromise of ...

, and the

Russian Empire The Russian Empire was an empire and the final period of the Russian monarchy from 1721 to 1917, ruling across large parts of Eurasia. It succeeded the Tsardom of Russia following the Treaty of Nystad, which ended the Great Northern War. ...

* 1955:

Warsaw Pact The Warsaw Pact (WP) or Treaty of Warsaw, formally the Treaty of Friendship, Cooperation and Mutual Assistance, was a collective defense treaty signed in Warsaw, Poland, between the Soviet Union and seven other Eastern Bloc socialist republic ...

– between

Albania Albania ( ; sq, Shqipëri or ), or , also or . officially the Republic of Albania ( sq, Republika e Shqipërisë), is a country in Southeastern Europe. It is located on the Adriatic and Ionian Seas within the Mediterranean Sea and shares ...

Bulgaria Bulgaria (; bg, България, Bǎlgariya), officially the Republic of Bulgaria,, ) is a country in Southeast Europe. It is situated on the eastern flank of the Balkans, and is bordered by Romania to the north, Serbia and North Macedon ...

Czechoslovakia , rue, Чеськословеньско, , yi, טשעכאסלאוואקיי, , common_name = Czechoslovakia , life_span = 1918–19391945–1992 , p1 = Austria-Hungary , image_p1 ...

East Germany East Germany, officially the German Democratic Republic (GDR; german: Deutsche Demokratische Republik, , DDR, ), was a country that existed from its creation on 7 October 1949 until its dissolution on 3 October 1990. In these years the state ...

Hungary Hungary ( hu, Magyarország ) is a landlocked country in Central Europe. Spanning of the Carpathian Basin, it is bordered by Slovakia to the north, Ukraine to the northeast, Romania to the east and southeast, Serbia to the south, Croatia a ...

Poland Poland, officially the Republic of Poland, is a country in Central Europe. It is divided into 16 administrative provinces called voivodeships, covering an area of . Poland has a population of over 38 million and is the fifth-most populous ...

Romania Romania ( ; ro, România ) is a country located at the crossroads of Central Europe, Central, Eastern Europe, Eastern, and Southeast Europe, Southeastern Europe. It borders Bulgaria to the south, Ukraine to the north, Hungary to the west, S ...

, and the

Soviet Union The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen national ...

United Kingdom

* 1955:

Middle East Treaty Organization The Middle East Treaty Organization (METO) is a non-governmental organization founded in 2017 by a coalition of civil-society activists and Nuclear disarmament, disarmament practitioners, with the aim to rid the Middle East of all Weapon of mass ...

– between

Iran Iran, officially the Islamic Republic of Iran, and also called Persia, is a country located in Western Asia. It is bordered by Iraq and Turkey to the west, by Azerbaijan and Armenia to the northwest, by the Caspian Sea and Turkmeni ...

Iraq Iraq,; ku, عێراق, translit=Êraq officially the Republic of Iraq, '; ku, کۆماری عێراق, translit=Komarî Êraq is a country in Western Asia. It is bordered by Turkey to Iraq–Turkey border, the north, Iran to Iran–Iraq ...

Pakistan Pakistan ( ur, ), officially the Islamic Republic of Pakistan ( ur, , label=none), is a country in South Asia. It is the world's List of countries and dependencies by population, fifth-most populous country, with a population of almost 24 ...

Turkey Turkey ( tr, Türkiye ), officially the Republic of Türkiye ( tr, Türkiye Cumhuriyeti, links=no ), is a list of transcontinental countries, transcontinental country located mainly on the Anatolia, Anatolian Peninsula in Western Asia, with ...

, and the

United States

* 1778: Treaty of Alliance – between the

Kingdom of France The Kingdom of France ( fro, Reaume de France; frm, Royaulme de France; french: link=yes, Royaume de France) is the historiographical name or umbrella term given to various political entities of France in the medieval and early modern period. ...

and the

* 1954–1977:

Southeast Asia Treaty Organization The Southeast Asia Treaty Organization (SEATO) was an international organization for collective defense in Southeast Asia created by the Southeast Asia Collective Defense Treaty, or Manila Pact, signed in September 1954 in Manila, the Philipp ...

– between

France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...

, the

Thailand Thailand ( ), historically known as Siam () and officially the Kingdom of Thailand, is a country in Southeast Asia, located at the centre of the Indochinese Peninsula, spanning , with a population of almost 70 million. The country is bo ...

, the

, and the

* 1955:

Sino-American Mutual Defense Treaty The Sino-American Mutual Defense Treaty (SAMDT), formally Mutual Defense Treaty between the United States of America and the Republic of China, was a defense pact signed between the United States and the Republic of China (Taiwan) effective from ...

– between

Taiwan Taiwan, officially the Republic of China (ROC), is a country in East Asia, at the junction of the East and South China Seas in the northwestern Pacific Ocean, with the People's Republic of China (PRC) to the northwest, Japan to the nort ...

and the

References

Defense Military alliances Treaties by type {{treaty-stub