From the Introduction: "The United States was the driving proponent of the North Atlantic Treaty Organization's (NATO) creation in 1949 and has been the unrivaled leader of the alliance as it has evolved from a collective defense organization of 12 members focused on deterring the Soviet Union to a globally engaged security organization of 30 members. Historically, U.S. Administrations have viewed U.S. leadership of NATO as a cornerstone of U.S. national security policy that brings benefits ranging from peace and stability in Europe to the political and military support of important allies, including many of the world's most advanced militaries. During his term in office, former President Donald Trump openly challenged long-standing U.S. support for NATO, however, arguing, among other things, that NATO was a 'bad deal' for the United States.[...] Many allies have welcomed President Joe Biden's pledge to renew U.S. support for NATO and to prioritize consultation and cooperation with allies.[...] Allied heads of state and government are expected to meet at NATO headquarters in Brussels, Belgium, in May or June 2021 to set NATO's agenda for the coming year."
CRS Report for Congress, R46066
Congressional Research Service: https://crsreports.congress.gov/