Roosevelt was the Democratic governor of New York and a distant cousin of Theodore Roosevelt. He defeated Herbert Hoover in a landslide in November 1932, by which time one in four American adults was jobless, nearly half of America's banks had failed and GDP had shrunk by 30%.
His remedy for the Great Depression was the New Deal in 1933, followed by the Second New Deal in 1935. In his second term he added a minimum wage, a 44-hour work week and overtime pay. By 1939 unemployment was still at 17%, but the New Deal entrenched a new idea: that in hard times the state should intervene more directly in the economy.
Roosevelt radically expanded presidential power. He gave his first message to Congress in person—something Woodrow Wilson had revived, but which now became standard practice. He brought legislation to Capitol Hill, cajoling and charming members rather than leaving Congress to set the agenda. He sold his ideas directly to the public through radio "fireside chats". In one such broadcast, in July 1933, he highlighted the passage of his New Deal in his first 100 days—a benchmark against which future presidents would be judged.
When the Supreme Court kept blocking New Deal policies, he threatened to expand it with six new justices. His "court-packing" scheme provoked a backlash. His decisions to run for a third and then a fourth term broke a longstanding two-term custom. The 22nd Amendment, ratified six years after his death, limits presidents to two elected terms.
In December 1940, Roosevelt declared that America "must be the great arsenal of democracy", arguing against the isolationist mood embodied by the America First Committee, whose most famous advocate was Charles Lindbergh. After Japan attacked Pearl Harbour on December 7th 1941—a date he said would "live in infamy"—America entered the second world war. More than 16m Americans served, roughly half of young men. America emerged as the world's unquestioned superpower.
During the war, the Roosevelt administration interned around 120,000 people of Japanese descent, two-thirds of them American citizens, on the grounds that they might otherwise engage in espionage or sabotage.
In 1939 Roosevelt received a letter written by Leo Szilard and signed by Albert Einstein warning of the destructive potential of an atomic bomb. Their message spurred him to act, ultimately leading to the creation of the Manhattan Project.
The difference between a good haircut and a bad one is seven days.