Public opinion has been part of US foreign relations in two key ways. As one would expect in a democracy, the American public has shaped the foreign policy of its government. No less significantly, the United States has sought to influence foreign public opinion as a tool of its diplomacy, now known as public diplomacy. The US public has also been a target of foreign attempts at influence with varying degrees of success. While analysis across the span of US history reveals a continuity of issues and approaches, issues of public opinion gained unprecedented salience in the second decade of the 21st century. This salience was not matched by scholarship.
Nicholas J. Cull
The United States was extremely reluctant to get drawn into the wars that erupted in Asia in 1937 and Europe in 1939. Deeply disillusioned with the experience of World War I, when the large number of trench warfare casualties had resulted in a peace that many American believed betrayed the aims they had fought for, the United States sought to avoid all forms of entangling alliances. Deeply embittered by the Depression, which was widely blamed on international bankers and businessmen, Congress enacted legislation that sought to prevent these actors from drawing the country into another war. The American aim was neutrality, but the underlying strength of the United States made it too big to be impartial—a problem that Roosevelt had to grapple with as Germany, Italy, and Japan began to challenge international order in the second half of the 1930s.