Franklin Delano Roosevelt was President of the United States of America from March 1933 until he died in office on April 12, 1945, a few days before Germany surrendered. He started office during the Great Depression and died towards the end of World War II. He was the leader of the Democratic Party during his Presidency.
Democratic Party loyalists portray Franklin Roosevelt as the savior of the nation. They believe his New Deal legislation helped Americans during the Depression, and was responsible for ending it. The continuance of most New Deal programs after the Depression ended is lauded as the beginning of a modern, well-adjusted state and economy. In addition, the defeat of America's World War II enemies, Germany under Adolf Hitler, Italy under Benito Mussolini, and Japan under Hideki Tojo, is attributed to Roosevelt's leadership, and is placed beyond criticism.
Republicans had a variety of criticism of President Roosevelt during his reign. Many criticized the New Deal, but most Republican members of Congress voted for many New Deal programs. [And many conservative Democrats in Congress voted against many of the programs.] There are two main, present-day criticisms of Roosevelt and the New Deal. One is that it did not end the Depression; rather it extended it be hampering businesses from getting on with the normal upswing in the economic cycle that usually follows a credit crisis of the type that characterized the Great Depression. The other is that even if it did help with the economy, it created a vastly larger, bureaucratic (possibly even socialist) government that should have been dismantled after the crisis was over.
The Republicans supported the war effort, but were not happy being allied with the USSR under Joseph Stalin. They are probably right that the war would have had the same results no matter who was President. Roosevelt himself said, before the U.S. had even entered the war, that Joseph Stalin had already beaten Hitler by winning the Battle of Moscow.
On the Great Depression issue, I would note that the New Deal was made of many pieces. Some, without a doubt, helped to get the U.S. economy going again. Some features did hamper businesses, and therefore the aggregate recovery of the business sector. What most clearly ended the Great Depression in the United States was the quicker revival of the German economy by the National Socialists (Nazis), followed by the rearmament boom in Europe and consequent export boom from the United States.
Another criticism leveled by Republicans, starting when Roosevelt announced he would run for a third term, was that Roosevelt was subverting democracy by making himself "President-for-life." When the nation came to its senses later, the XXII Amendment to the United States Constitution was passed, limiting Presidents to two terms of office. However dictatorial Roosevelt may have acted at times, however, he did leave the two party system intact. He also left the system of racial segregation, including denying black Americans the right to vote, intact in the former states of the Confederacy. Thus, in running a racist, militarist, bureaucratic regime similar to that of the National Socialists in Germany, the main differential that prevents the Roosevelt administration as being labelled as truly fascist is that, unlike Hitler, Roosevelt did not have his domestic opponents murdered (excepting probably Governor Huey Long, who was a Democrat).
Americans seldom look at Franklin Roosevelt's life prior to his election to be President. I will go over it in detail in more detail in another essay. Most people know he came from a wealthy family and was related to President Theodore Roosevelt. A person like that is handed offices at an early age that an unconnected person might have to work all their lives to obtain. He started as a Wall Street corporate lawyer, but was elected to the New York State Senate in 1910 at the age of 28. He was appointed Assistant Secretary of the Navy at the age of 31. As such he participated deeply in the U.S. attacks on Latin American nations during that era. Whatever else he was, he was a life-long militarist who dreamed of a triumphant white America ruling over an empire of colored people similar to the British Empire.
Roosevelt and other U.S. imperialists were well aware of the complexity of international relations. In 1936 Roosevelt was happy to let Franco, Mussolini, and Hitler impose a fascist government on Spain without a contest. Like most capitalists, he saw Stalin's USSR as the main danger. The economy of the U.S.S.R. had grown markedly since the Russian Revolution, while those of the capitalist nations were in obvious decline. Communists and the Japanese, while bitter rivals, were also getting the better of the U.S. puppet in China, Chiang Kai-shek. Roosevelt could not hope to take over Europe, and the U.S. already ruled over all of the Americas (for practical purposes). Africa was occupied by the British. That left only East Asia as a hunting ground for Roosevelt.
By profiteering from the plight of the British Empire while watching Stalin and Hitler do most of the real fighting, Roosevelt did a better job for American imperialism than he planned. By maneuvering Japan into a war over China, however he made a big mistake.
After Roosevelt's death and the end of World War II, the United States largely supplanted Great Britain as the world's greatest imperial power. This was Roosevelts greatest legacy. In addition to the war crimes committed at his command during the war, it would lead lead the U.S. to the long road of troubles every imperialist nation experiences. While the U.S. retained control of the Philippines and occupied Japan and Korea, its Asian strategy backfired, which became more obvious as decades passed. Japan itself could not be exploited to the extent originally intended because it was needed to balance communist military and economic power. China was taken out of the U.S. economic block by its own communist movement. Japan had shown that White Power was not invincible, and most East Asian nations continued their struggles for independence from their colonial masters. The U.S. has only been able to hold on to South Korea and the Philippines as quasi-colonies.
In summary, Roosevelt did some good things, like getting Social Security started. He missed an opportunity to create a national, government-run medical insurance program. He greatly increased the authority of the federal government, and within it he increased Presidential power, thus undermining democracy. He forced Japan into an unecessary war, and only attacked Hitler because he thought if he did not Stalin would take over Europe. He also ordered the creation of nuclear weapons, which is probably the greatest tragedy of the 20th century.