And not much time, at that. Calvin Coolidge may not have spoken for all Americans when he proclaimed that the business of America was business, but he spoke for those who counted during the Republican decade after the war. Disillusionment with the war's outcome—millions killed, including 60,000 Americans, to little positive effect observable from across the Atlantic—reinforced the feeling that Washington and Jefferson had been right. Foreign entanglements were a fool's game. There was still American engagement abroad, but it was chiefly the engagement of private, corporate interests, backed at times by federal officials (including the bright new star of the Republicans, Commerce Secretary Herbert Hoover) yet rarely rising to the level of a widely supported national interest.
If anything, the national interest seemed to point in precisely the opposite direction. During the latter half of the 1920s, the authors Harry Elmer Barnes, C. Hartley Grattan, and others attacked American participation in the late war as the work of private interests—chiefly financial and mercantile—parading as the national interest. During the 1930s this attitude enveloped Capitol Hill, where an investigative committee headed by Senator Gerald Nye laid blame for America's feckless involvement in the war at the feet of the "merchants of death." The Nye committee provided ammunition to congressional isolationists, who legislated neutrality for the United States in the event of another war. Yet this was a different neutrality from that which had defined much of the national interest from the 1790s to the 1910s. Where America's historic neutrality had been actively defended, twice by war (in 1812 and 1917), the legislated neutrality of the 1930s would be preserved by abandoning American neutral rights. The Neutrality Act of 1937, for example, forbade the sale of munitions to belligerents (no more "merchants of death"), outlawed loans to belligerents (no more lopsided lending) and barred American travel on belligerent ships (no more Lusitania s—or at least no more American deaths on such ships). The neutrality law also allowed the president to insist that trade in goods other than munitions be conducted on a cash-and-carry basis, with the purchasers taking responsibility for the cargoes before they left U.S. shores (no more American ships showing up in the crosshairs of belligerent periscopes).
Americans might have quibbled over the details of the neutrality laws, but by all evidence they supported the general idea. Twenty years after the fact, American involvement in World War I seemed an exercise in fatuity, the likes of which should be avoided at nearly all cost.
Yet no sooner had they reached this consensus than events began to erode it. In appallingly short order, Italy brutalized Ethiopia, Japan raped China, and Germany severed Czechoslovakia. Many Americans thought it would be impossible to retain the country's self-respect without taking action against the organized violence abroad. Others concluded that if the violence was not stopped now, it would inevitably engulf the United States, as it had in World War I. But still others came to the opposite conclusion: to them, the muggings abroad underscored the necessity of neutrality. If the world insisted on going to hell, let it do so, but do not let it take America down with it.
The outbreak of the second great European war of the twentieth century, in September 1939, polarized American opinion further. A group calling itself America First wanted to widen the Atlantic and Pacific oceans and keep American boys securely at home. Mere discussion of U.S. intervention, the America Firsters said, discouraged Britain and France from doing for themselves what needed to be done. An opposing group, the Committee to Defend America by Aiding the Allies, advocated a forthright policy of supporting those countries opposing Nazi Germany. With luck, such support might stop short of American belligerence, but that ultimate step could not be ruled out—nor should it be, lest Adolf Hitler take heart from American aloofness.
This latest round of the debate over the national interest continued for two years, until the Japanese attack on Pearl Harbor. As even the narrowest definition demanded defending American territory, by transgressing U.S. borders the Japanese guaranteed American belligerence. Had Hitler not gratuitously declared war on the United States while the waters of Hawaii were still stained with American blood, debate doubtless would have continued regarding whether the national interest required fighting Germany. But in the event, Americans entered both wars—in the Pacific and in Europe—united in defining the national interest as requiring the defeat of the Axis. Woodrow Wilson might have been wrong about some things, but he now seemed right about America's inability to insulate itself from a world at war.