Answer:
U.S. war spending helped add $236 billion to the debt. It was a 1,048% increase, the largest percentage increase to the debt of any president.
A review of U.S. gross domestic product growth by year reveals that the economy grew at least 8% annually between 1939 and 1944. Between 1941 and 1943, it grew more than 17% a year.
One reason U.S. production grew so fast was that it had been slack during the Great Depression. Underutilized manufacturing, shipbuilding, and auto factories were able to gear up for full production.
To pay for it, the government expanded the income tax and introduced mandatory withholdings from paychecks. In 1939, 4 million Americans paid federal taxes. That rose to 43 million by 1945.
The war turned the United States into a major military power. Before the war started, the U.S. Army only had 174,000 troops. That was 19th in the world and smaller than Portugal's. Army Chief of Staff General George C. Marshall reorganized the army into a strong fighting force. In December 1941, it had grown to 1.8 million men. By 1945, it had 8.25 million.
In 1947, the Truman Doctrine pledged the United States to assist any democracy attacked by authoritarian forces.It shifted U.S. foreign policy from isolationist to the global policeman. The Marshall Plan pledged $12 billion in food, machinery, and foreign direct investment to rebuild Europe.The National Security Act consolidated the Army and Navy into the Defense Department. It created the Air Force, the National Security Council, and the CIA. In 1948, the United States airlifted food and fuel in West Berlin after the Soviets blockaded it.
In 1949, the Fair Deal called for national health insurance and raising the minimum wage. It also proposed the Fair Employment Practices Act to make illegal any religious and racial discrimination in hiring. Congress rejected national health insurance but passed the rest of the Fair Deal.
The Immigration and Nationality Act of 1952 continued quotas for immigrants based upon country of origin. It had lower quotas for Asians, a vestige of the racism prevalent during the war. Between 1942 and 1945, the federal government relocated 117,000 Americans of Japanese ancestry into internment camps. The Act prioritized family reunification and desired skills.