After his first inauguration in January 1933, Roosevelt moved rapidly to undertake the kind of programs and regulation he believed were needed to save the country from the Great Depression's catastrophic fallout— including a record 25 percent unemployment. He rolled out new banking and securities laws, created dozens of new government agencies, set up relief programs and sought to rein in free-market capitalism with centralized industry-wide rule making.

The Supreme Court promptly ruled that many of his initiatives were unconstitutional, including the National Industrial Recovery Act, which sought to impose standards and eliminate unfair labor and trade practices. An irate FDR spoke out against what he dubbed the “horse and buggy” mentality of many of the justices, most of whom had been born before 1880.

Immediately following his landslide re-election in 1936, the president devised a potential workaround: He asked Congress for permission to appoint a new justice to the court for each one who hadn’t retired by the age of 70. That would have effectively expanded the court to 15 members. A bitter Congressional battle followed; after the sudden death of the president’s Senate ally, Joe Robinson of Arkansas, Congress defeated the court-packing measure. Still, during his long tenure, F.D.R. had the chance to name eight new Supreme Court justices, laying the groundwork for a different judicial environment.

In early 1937, New York Senator Robert F. Wagner and Indiana Senator Frederick Van Nuys proposed a federal bill that would hold law officers responsible if their “negligence” contributed to a lynching. FDR wouldn’t support the bill. While he was no racist (he entertained Black visitors in the White House and had Black advisors), he didn’t want to spend his political capital fighting southern “Dixiecrats” over the proposed legislation. “If I come out for the anti-lynching bill now,” the president told an official of the National Association for the Advancement of Colored People (NAACP), “they will block every bill I ask Congress to pass to keep America from collapsing. I just can’t take the risk.” And while the president’s wife, Eleanor Roosevelt, stepped into the breach and became a vocal opponent of institutional racism, the anti-lynching bill collapsed.

As the 1930s progressed, rising anti-Semitism in Adolf Hitler’s Germany caused new headaches for Roosevelt. By 1939, the U.S. immigration quota allowed fewer than 30,000 Germans to come to the United States—a tenth of the number seeking admission as Hitler’s repression became more violent. The quota also banned the admission of anyone likely to become a public charge. That meant that many Jewish refugees, stripped of their assets before fleeing, couldn’t come to the U.S. legally, unless Roosevelt intervened.

But the president didn’t follow the advice of his Secretary of Labor Frances Perkins, who suggested he sign an executive order giving priority to refugees fleeing persecution. Later, the president again failed to intervene by allowing any of the 900-plus refugees aboard the German ocean liner St. Louis to land in the United States. (About a third of its passengers later perished in the Holocaust after being forced back to Europe.) It wasn’t until 1944, as the full horror of the Holocaust was becoming clear, that F.D.R. created the War Refugee Board to aid civilian victims of Nazi persecution.

Was it hubris or a single-minded determination to ensure leadership continuity amid the storms of war? Whatever the reason, Roosevelt opted to seek a third term in office in 1940, hoping to stem the wave of isolationism in Congress and consolidate his economic policies. While not illegal, the move caused unease on both sides of the political aisle. Wendell Wilkie, his Republican opponent, criticized the decision, arguing that “if one man is indispensable, then none of us is free.” F.D.R. handily beat Wilkie, becoming the first and only president elected to a third term; he would seek and win a fourth in 1944. The 22nd amendment, ratified in 1951, banned anyone else from trying to emulate this feat.

On December 7, 1941, the Japanese military staged a devastating surprise attack on the U.S. military forces stationed at Pearl Harbor, Hawaii, drawing America into World War II. Only months later, in February 1942, Roosevelt signed Executive Order 9066 authorizing the military to incarcerate some 120,000 people of Japanese descent—two thirds of them American citizens—in remote inland camps. Stripped of their civil rights, many lost their homes, farms and businesses in the process. Ultimately, many young Japanese Americans would fight—and die—for their country, even while their family members languished in the incarceration camps. Not until 1988 did the U.S. government formally apologize and offer restitution.

Roosevelt, who embraced the label of “progressive” while in practice remaining fiercely pragmatic, attracted fierce criticism from both ends of the political spectrum. Those on the right denounced him as a socialist for the ways in which he expanded both presidential powers, grew the role of the federal government and levied new, higher taxes on individuals and businesses. Those on the left argue that his policies didn’t go nearly far enough—and that Congress had granted Roosevelt powers that made him the equivalent of a totalitarian leader.