He built the New Deal Coalition, which defined modern liberalism in the United States throughout the middle third of the 20th century. His third and fourth terms were dominated by World War II, which ended in victory shortly after he died in office.
Born into the prominent Roosevelt family in Hyde Park, New York, he graduated from both Groton School and Harvard College, and attended Columbia Law School, which he left after passing the bar exam to practice law in New York City. In 1905, he married his fifth cousin once removed, Eleanor Roosevelt. They had six children, of whom five survived into adulthood. He won election to the New York State Senate in 1910, and then served as Assistant Secretary of the Navy under President Woodrow Wilson during World War I. Roosevelt was James M. Cox's running mate on the Democratic Party's 1920 national ticket, but Cox was defeated by Republican Warren G. Harding. In 1921, Roosevelt contracted a paralytic illness diagnosed as polio  and his legs became permanently paralyzed. While attempting to recover from his condition, Roosevelt founded a polio rehabilitation center in Warm Springs, Georgia. 