As of 2015, the United States' current allies include countries with which the United States has pledged allegiance through joint defense treaties, including NATO, the Japanese Treaty and the Rio Treaty. In some cases, the United States considers another country an ally when the two countries' trade goals align closely, such as the case with the North American Free Trade Agreement with Mexico and Canada, and the United States' oil endeavors with Saudi Arabia.
The United States' most notable defense alliances are with the 27 other NATO countries, including the United Kingdom, France and Germany. Smaller defense agreements with countries including Japan and South Korea ensure that the United States would act to assist these countries against aggression from other countries in most cases. Similar alliances established by defense treaties are the Rio Treaty between the United States and many Central and South American countries, the Philippines Treaty, the Southeast Asia Treaty and the formal agreement between the United States, Australia and New Zealand.
The United States also establishes alliances based on strategic international relations. For example, the United States has historically offered Israel military support and protection in return for a strategic partnership in a volatile region of the world.
Though not as concrete as alliances built around collective defense agreements, the United States often fosters alliances based on trade goals. Collective North American trade interests have led the United States to become economically aligned with Canada and Mexico, along with several other peaceful trade partners around the world.