1941 Pearl Harbor: Japan's surprise attack on an American naval base in Hawaii 70 years ago forced the U.S. into World War II.

• Author: Perlman, Merrill
• Position: TIMES PAST

For William Czako, a 28-year-old from Fremont, Ohio, the naval assignment must have felt like a gift: sunny skies, palm trees, and white-sand beaches.

But on the sleepy Sunday morning of December 7, 1941, the tropical paradise of Pearl Harbor, a naval base in the U.S. territory of Hawaii, suffered what was then the largest attack on American soil in the nation's history.

"We've been bombed now for an hour," Czako began writing in a letter to his sister at 9:05 a.m. that morning. "They really caught us in our sleep this time."

Dropping hundreds of bombs and new shallow-water torpedoes, Japanese fighter planes sank or destroyed a dozen ships, from battleships to cruisers, and damaged or demolished hundreds of planes, killing or wounding thousands of Americans in a surprise attack.

Overnight, the United States was forced to enter World War II, changing the course of the war and reshaping the world in ways that are still felt today.

"It's hard to think of an event that had more profound changes for the world and certainly equally profound changes for the country," says James Gormly, a professor of history at Washington & Jefferson College in Pennsylvania.

'None of Our Business'

Before that fateful day, sentiment about the war then ravaging Europe fell largely into two camps. Isolationists believed the security of the U.S. was best served by staying out of a war that England, France, and the Soviet Union--U.S. allies--were fighting against Nazi Germany and its ally fascist Italy (see map, facing page). Isolationist sentiment ran especially high during the Great Depression: In a 1935 poll, 39 percent of college students said they would refuse to fight in a war, even if the U.S. was invaded.

But on the other side of the spectrum, a growing number of Americans began to realize the grave threat posed by Germany and its anti-Semitic dictator, Adolf Hitler.

President Franklin D. Roosevelt was caught in the middle. In his State of the Union address in January 1940, Roosevelt said he understood those wanting to stay out of the war. But he insisted that "there is a vast difference between keeping out of war and pretending that this war is none of our business."

Realizing that war was a real possibility, Roosevelt instituted a number of measures in the next year, including doubling the size of the U.S. Navy, pushing Congress to pass the first peacetime military draft, and supplying weapons and military hardware for ships and planes to the Soviet Union, England, and France through the "Lend-Lease" program.

In the Pacific, Japan had imperial intentions of its own: Resource-poor, it craved control over East and Southeast Asia and their raw materials to feed its growing manufacturing economy.

Japan joined forces with the Axis powers of Germany and Italy in 1936. A year later, it declared war on China, prompting the U.S. to cut off sales of iron, steel, fuel, and other materials Japan desperately needed to keep its war machine going.

Japan decided it needed to weaken the U.S., or at least keep it out of the Pacific. There were signs that Japan might launch an attack, but in the days before satellites and superpowerful radar could detect foreign troop movements, long-range intelligence was hard to come by. So it was relatively easy for Japan to discreetly send its fleet thousands of miles across the Pacific Ocean to Hawaii.

The attack on Pearl...