The United States is one of several countries to have used nuclear weapons in warfare.
Nuclear proliferation . Proliferation has been opposed by many nations with and without nuclear weapons , the governments of which fear that more countries with nuclear weapons may increase the possibility of nuclear warfare ( up to and including the so-called `` countervalue '' targeting of civilians with nuclear weapons ) , de-stabilize international or regional relations , or infringe upon the national sovereignty of states . United States . The United States emerged from as a global superpower , the first country to develop nuclear weapons , the only country to use them in warfare , and a permanent member of the United Nations Security Council .