America First?

President Donald J. Trump's 2016 election campaign aroused fears among European North Atlantic Treaty Organization (NATO) allies about U.S. commitments to collective defense. One of his closest supporters, Newt Gingrich, announced that he would not risk a nuclear war over some place in "the suburbs of St. Petersburg." Was U.S. interventionism coming to an end? Trump's new foreign policy seemed tantamount to isolationism. Thus, case studies of U.S. decision-making prior to entering the First and Second World Wars, U.S. involvement in NATO, and resistance within the Senate to large numbers of U.S. troops in Europe in the 1960s and 1970s help to trace the evolution of isolationism in U.S. statecraft. Congressional partisanship, public opinion, and domestic political issues shaped U.S. foreign policy of the past. Hence, experts of U.S. political history should not be surprised about Trump's foreign political agenda.