Military alliances of the United States

The United States is currently the most powerful country in the world, and the most influential in global politics. Part of this influence is exerted through the US’ network of alliances, which covers much of the globe. The many allies of the US both provide the US with support in conflicts, deterrence and power projection, and overall serve as a completely necessary part of what makes the US into the world’s only true superpower.

The purpose of this article is to serve as a more complete list of US military alliances than what yours truly has found online. This is an idea I’ve had for some time, and the times we live in have been so kind as to give us a very good reason to look at what obligations the US actually has, and what countries are its actual allies.

It is hard to define and delimit what a military alliance is. In this article a country is considered to be an ally of the United States if it fulfils at least one of three criteria:

The country is referred to as an ally by the United States through official channels, or a nominal definition.
The country is subject to a treaty which provides for mutual defense with the United States, or a defensive definition.
The country is carrying out significant security cooperation with the US, or a cooperative definition.

A comprehensive map of what is covered in the article. Maps made using mapchart.net.

The US is in two main multinational alliances, those being the North Atlantic Treaty Organization (NATO) and the Organization of American States (OAS). Of the two, only NATO is considered a military alliance, and is the most important defense obligation of the US.

Important allies outside of NATO may be designated as a Major Non-NATO Ally (MNNA) by the president, which allows a greater degree of cooperation between the country and the US. How much actual cooperation the US actually has with the countries varies.

Flag of NATO

NATO

The North Atlantic Treaty Organization was founded in 1949, and at the time of writing has 32 member states. The organization is an alliance by all three definitions outlined above. NATO is referred to as and intended as an alliance, it entails mutual defense through article 5 of the NATO treaty, and a NATO member is eligible for any possible type of US security cooperation.

The population of all 32 member states of NATO combined add up to almost a billion people, of which the US is about a third. In economic terms, NATO is about half of the world’s economy and half of the world’s defense spending.[1] Of this, the US is about half of NATO’s economy, or a quarter of the global economy, and about two thirds of NATO’s defense spending. By every measure NATO is the most important military alliance in the world, and is the most important piece of American foreign policy.

NATO has major overlap with the European Union, and 23 of the EU’s 27 members are also members of NATO. The EU is not just a political and economic union, but is also a security framework. Article 42.7 of the Treaty of the European Union states that an attack on any EU member must be answered by all means in the power of all other members. Should an attack occur against any of the four non-NATO EU members more than half of NATO would already be engaged.

Apart from the EU defense partnership, NATO members Turkey and the UK also have defense agreements with three non-NATO countries. Turkey is bound to Azerbaijan through a series of defense agreements. The UK, together with Australia and New Zealand, guarantee the defense of Singapore and Malaysia in the Five Powers Defence Agreements.

Three countries are official candidates for joining NATO. These three are Bosnia, Georgia and Ukraine. Ukraine is the most interlinked with NATO currently, as a result of the Russian invasion of its territory. While Ukraine has not been given any special nominal status, a number of US laws have been passed that simplify the process of providing aid to Ukraine, giving Ukraine in practice most of the same privileges of a MNNA.[2] This relies, like all other alliances, of the US government actually following up their obligations.

OAS and Rio Pact

The Organization of American States is not a military alliance, but article 28 of the OAS charter is a mutual defense article, stating that an attack on one is an attack on all. A more comprehensive security agreement within the OAS is the Inter-American Treaty of Reciprocal Assistance, otherwise known as the Rio Pact. The Rio Pact serves to specify what an armed attack is, what to do when threatened by one and what to do when an armed attack comes.

Not all OAS members are signatories to the Rio Pact. Multiple leftist Latin American regimes have withdrawn their signatures or never joined the pact to begin with, viewing a defense partnership with the US as a sign of approval of US imperialism. While the OAS charter states that all American countries must defend any other in case of attack, including the US, it remains an open question which other countries would support American interests in a hypothetical defensive war.

An amusing edge case within the OAS is that Venezuela’s government announced in 2017 that the country would leave the OAS, a decision the US does not recognize.[3] This means that the US claims to have a responsibility to defend Venezuela in the event Venezuela gets attacked, while Venezuela claims the US does not have any such responsibility.

Major Non-NATO Allies

By official US designation there are 19 MNNAs, and Taiwan, which is treated as an MNNA according to US law.[4] The designation as MNNA allows the US government to enter greater cooperation with the country without going through congress and various administrative barriers, which would be needed if the country was not designated as such. The designation does not automatically mean that actual cooperation is going on, and a couple of MNNAs have shifted away from being effective allies of the US.

The westernmost three and the easternmost six (official) MNNAs are in mutual defense agreements with the US, while the middle ten are not. The three western MNNAs, i.e. Brazil, Argentina and Colombia, are parties to the Rio Pact. The MNNAs in the Asia-Pacific are all guaranteed mutual defense with the US through bilateral or trilateral agreements made during the cold war.

Two countries have the status of Major Defense Partner, those being India and the UAE.[5] This designation is less comprehensive than the MNNA designation, but it allows those two greater privileges than any given non-NATO non-MNNA country.

De facto allies

The countries discussed so far are either nominally allied to the US, allied to the US through mutual defense treaties, or both. These “official” allies make up most of the alliances of the US, but there are quite a few countries that have a high degree of security cooperation without any official designation. That number is falling, however.

In 2015, US president Barack Obama raised the possibility of designating the rest of the Gulf Cooperation Council (GCC) as MNNAs.[6] The two GCC members Kuwait and Bahrain were already MNNAs, while the US had some degree of military cooperation with the rest. Since then, Qatar has been designated as an MNNA and the UAE as a Major Defense Partner, but Saudi Arabia and Oman remain without any official designation. The US maintains armed forces bases in both Saudi Arabia and Oman, and is the main arms provider for both countries.

The US was active in West Africa in cooperation with France to counter jihadist terrorist movements, and for that purpose had forces and bases stationed in multiple countries. A series of coups in former French colonies have replaced western-friendly, semi-democratic regimes with military juntas that are weary and wary of western influence, that have one by one expelled all American forces from their countries. American forces in Western and Central Africa, that were once present all over the region, now remain only with a toehold presence in Cameroon.

The Association of South-East Asian Nations (ASEAN) is an intergovernmental organization that the US maintains security cooperation with. The cooperation is done both between the US and ASEAN as an organization, and between the US and the countries individually. It mainly concerns naval and coast guard issues. Former president Joe Biden designated ASEAN collectively as a Comprehensive Strategic Partner, which doesn’t mean much in terms of cooperation but signifies a better relationship on paper.[7]