President Franklin D. Roosevelt overstated the threat, too. (Linda Davidson/The Washington Post)
Matthew Dallek, an associate professor at George Washington University’s Graduate School of Political Management, is author of "Defenseless Under the Night: The Roosevelt Years and the Origins of Homeland Security."

Donald Trump has likened his proposed anti-Muslim clampdown to wartime security steps taken by the United States after the bombing of Pearl Harbor. “What I’m doing is no different from FDR,” Trump claimed in an interview with ABC News, referring, presumably, to Japanese American internment camps, nationality checks and curbs on Italians and Germans in the United States. These measures, in Trump’s view of history, helped FDR protect the home front and win the war against fascism; his proposals are merely their modern analogues.

The New York real estate tycoon-turned-GOP-front-runner is correct when he invokes the World War II analogy. Just not in the way that he thinks. Those measures did nothing to help defeat the Axis, but they coincided with a surge of mass hysteria, xenophobia and paranoia about what America’s enemies could do. Trump has tapped into similar fears that dominate today’s public mood and shape our political debate. Are his plans worth considering? The answer lies in what happened when politicians fanned those fears 75 years ago.

In the years leading up to Pearl Harbor, a similar sense of hysteria about America’s safety gripped much of the news media, federal and city elected officials and military commanders. The media invoked the specter of air raids on Los Angeles, New York City and other major metropolitan areas. War games in the United States became commonplace. Talk of Nazi inroads in Latin America spiked, while officials in charge of public safety sought to ferret out spies and saboteurs who were allegedly threatening the civic order. Maps appeared in the United States showing flying times from various islands in the Western Hemisphere to U.S. cities, with Nazi swastikas emblazoned over the arrows pointing towards densely populated regions. The fall of France prompted San Antonio’s liberal Mayor Maury Maverick to fret that if his city did not receive defense aid from Washington soon, San Antonio could fall to the Nazis just like Paris had fallen.

There was hardly any evidence of a legitimate threat within, but that didn’t mean much to those who were doing the fear-mongering. New York City Mayor Fiorello La Guardia, who in 1941 was also director of the U.S. Office of Civilian Defense, warned in the Los Angeles Times that a single air raid could have Americans “gibbering” and lead to “a sweeping conflagration of insanity” on city streets. Mass panic, he predicted, would cause New Yorkers to trample each other to death as they fled skyscrapers and dashed to board subway trains to escape incendiary and high-explosive bombs.

That was all prior to Pearl Harbor. The hysteria that Trump is channeling and fomenting is under the circumstances more invidious than the level of panic-fueled policy pronouncements reached during World War II. By July of 1940, Hitler’s Wehrmacht and Luftwaffe had won swift, stunning victories over many of America’s European allies. While Americans reasonably could, and often did, conclude that fascism had become an existential threat to American democracy, the Islamic State — a death cult capable of enormous acts of evil, to be sure — hardly poses a similar such total threat to the world’s strongest military and economic power.

After the attacks on Pearl Harbor, American hysteria reached a fever pitch. Worries that the nation would be attacked (land invasion via Mexico, air raids launched from island bases, aircraft carriers or even from Europe; sabotage, air raid panics) sparked a big debate among liberal leaders about how best to protect the home front and defend American lives. In February 1942, even FDR told reporters that “the Nazis can come in and shell New York tomorrow night, under certain conditions. They can probably, so far as that goes, drop bombs on Detroit tomorrow night, under certain conditions.”

In response to such hysteria, beyond the mass incarceration of Japanese Americans, much of the country became militarized. The Army and U.S. officials led efforts to black out regions, enforce lighting restrictions, monitor suspicious activities, impose curfews on enemy aliens and conduct air raid drills that led to chaos and actually killed some civilians (one Washingtonian fell off a building and died as alarms in the city sounded). In Los Angeles, the belief that the city was under attack — the report proved false — led to heart attacks and traffic fatalities. Some Seattle residents rioted when fellow citizens refused to comply with blackout rules. A program to dim the lights on the Eastern Seaboard had the desired effect of making it harder for Nazi subs to see U.S. merchant ships ferrying supplies to Europe, and saved some lives and U.S. cargo. But many of the other restrictions were irrational responses to the actual level of threat facing Americans, and arguably didn’t make citizens any safer. There were no true military battles against Axis powers in the continental United States during the war.

The decision to intern Japanese Americans after Pearl Harbor and curb the rights of Italians and Germans were  gross violations of civil liberties and, ultimately, were widely repudiated. Such clampdowns fanned racist sentiment at home and provided ideological fodder for the Axis Powers propagandizing against the U.S. overseas. What’s more, they didn’t actually make the country any safer. The national policies that helped win the war – the Selective Service and Training Act, the Lend-Lease Act, military-industrial mobilization, Roosevelt’s Four Freedoms and Economic Bill of Rights addresses – had little to do with American attitudes about interlopers. Trump, of course, isn’t proposing anything like these.

Trump says our homeland is acutely vulnerable to foreign enemy attacks directed by the Islamic State – a claim that echoes the politics of mass hysteria that pervaded the late 1930s and early 1940s. Americans are buying guns in record numbers, Trump has proposed barring all non-U.S. Muslims from entering the United States, and he wants the government to step up surveillance of mosques and Muslim American communities. He implies a conspiracy: “There is something wrong with him that we don’t know about,” he said of President Obama, implying once again that he is somehow foreign or un-American.

We’ve been down this road before.