The United States maintains formal diplomatic relations with most nations globally, including nearly all UN members and observer states, notably excluding Bhutan, Iran, North Korea, and the Palestinian Territory. Holding the second-most diplomatic posts worldwide after China, the U.S. has significantly influenced international relations, particularly in Eastern Europe where post-Cold War states transitioned to democracy and many joined the EU and NATO.

In the Greater Middle East, key allies like Turkey (a NATO member), Israel, and Egypt receive substantial U.S. foreign aid, with Israel receiving $2.775 billion and Egypt $1.75 billion in 2010. Furthermore, the U.S. has deep economic and geostrategic partnerships with ASEAN countries, signing their Treaty of Amity and Cooperation in July 2009 to promote regional peace. Despite these extensive ties, the U.S. currently experiences strained relations with several nations, including prominent countries like China, Russia, Iran, North Korea, and Venezuela.