This article was originally posted at Providence.

Twelve days before the Japanese attack on the United States at Pearl Harbor, one of the nation’s most prominent liberal clergymen, Charles Clayton Morrison, denounced the growing talk of American involvement in the European war against Nazism. As editor of the Christian Century, Morrison had used his influential magazine to support every international peace plan imaginable to avoid a confrontation with Hitler’s resurgent Germany. All of those schemes had failed—while most of Europe lay prostrate before the German Wehrmacht.

Nevertheless, Morrison was unmoved. Talk of an Anglo-American alliance to defeat fascism, he wrote on November 26, 1941, “concealed the most ambitious imperialism every projected.” An Anglo-American victory in Europe, he intoned, would simply replace one kind of dictatorship with another:

The American citizen, with his boundless beliefs in his own capacities, is asked to prepare to fight a war so that he and his kind can take over the control of the world…Many Christians, who have finally brought themselves to consent to American entrance into the war as a means of destroying Hitler, have not yet grasped the potency of this dark logic, which will turn victory into the proclamation of a new imperialism.

President Franklin Roosevelt called the Japanese surprise attack on December 7 “a date which will live in infamy.” Perhaps an even greater infamy was the vacuous form of liberalism that denied the existence of radical evil, making it almost incapable of distinguishing between flawed democracies and fascist barbarism.

Groomed on Wilsonian idealism, Roosevelt had imbibed the spirit of the age. Like his European counterparts, the president responded meekly to the rise of totalitarianism in Europe and Asia. Japan’s brutal war in China, beginning in 1937, had revealed a nation in crisis: a despotic and militarized society. “Long before the European war broke out, Japan was a tense, underfed, increasingly desperate totalitarian country,” writes historian Paul Johnson, “which had alienated all its neighbors, abolished its constitutional and democratic system, abandoned the rule of law…and had adopted the expedient of using force to smash its way out of its difficulties, which were increasingly self-created.”

When the Japanese signed the Tripartite Pact with Germany and Italy in September 1940, there was no change in America’s foreign policy posture. In July 1941, when Japanese forces occupied French Indochina, Roosevelt authorized sanctions against the Japanese. But at Pearl Harbor, the main Pacific base of the American fleet, it was business as usual. Even after two years of Nazi victories in Europe, with Great Britain struggling for survival, FDR sought no significant build-up of U.S. military forces. As the president declared during his 1940 re-election campaign: “I have said this before, but I shall say it again and again and again: Your boys are not going to be sent into any foreign wars.” When the Japanese attack came, there were about 188,000 men in the American army, which in troop strength put it somewhere between Bulgaria and Portugal.

On December 7, 1941, America’s isolationist fantasy turned to fairy dust. Roosevelt’s speech to Congress the next day is rightly praised for its determination to marshal the nation’s resources to defeat her enemies. “No matter how long it may take us to overcome this premeditated invasion,” he said, “the American people in their righteous might will win through to absolute victory.”

Yet it was another speech to Congress, a few weeks later, on December 26, that laid bare unpleasant truths left unspoken by the American president. When Winston Churchill appeared before a joint session of Congress, he drew attention to the dangerous folly of democratic weakness in the face of international aggression. “We have performed the duties and tasks of peace,” he said. “They have plotted and planned for war.” But the pacifist impulse, indulged in by both Great Britain and the United States, had been a mistake. “If we had kept together after the last war, if we had taken common measures for our safety, this renewal of the curses need never have fallen upon us.”

Although delighted and buoyed by America’s entry into the war, Churchill nevertheless thought it necessary to offer a painful history lesson. In a subtle criticism of Roosevelt’s pre-war leadership, Churchill reminded his new ally of the wretched cost of the policies of appeasement:

Five or six years ago it would have been easy, without shedding a drop of blood, for the United States and Great Britain to have insisted on fulfillment of the disarmament clauses of the treaties which Germany signed after the Great War…That chance has passed. It is gone. Prodigious hammer-strokes have been needed to bring us together again.

The painful and prodigious hammer-strokes would continue unabated. Within weeks of Pearl Harbor, Japanese forces advanced across the Pacific and South-East Asia in a daring offensive that left American and British troops staggering in defeat and surrender. By the spring of 1942, Japan had executed a blitzkrieg of its own, as devastating as that of the Germans in Europe.

But the Japanese, like the Germans, had vastly underestimated the martial fury of the American people once they are forced into war. Virtually overnight, the United States overcame its deficit of moral seriousness: nonsense talk about American imperialism gave way to a message of national unity to defeat totalitarianism. Pearl Harbor accomplished in an instant what the American president could never have achieved on his own: it persuaded the United States to engage in a total war, a just war, with every ounce of its combined economic and military strength.

Now, finally, the “arsenal of democracy” would do its work.