The United States is a member of the following international associations from your list:
- United Nations - The U.S. is one of the founding members of the UN and plays a significant role in its operations.
- North Atlantic Treaty Organization (NATO) - The U.S. is a founding member of NATO, a military alliance established in 1949.
The United States is not a member of the following:
- Warsaw Pact - The U.S. was never a member of this military alliance, which was dominated by the Soviet Union and included Eastern Bloc countries.
- League of Nations - The U.S. was involved in the creation of the League of Nations but never joined.
- British Commonwealth - The U.S. is not a member of the Commonwealth; it is a separate nation.
So, the United States belongs to the United Nations and the North Atlantic Treaty Organization (NATO).