In 1944 FDR was reelected to an unprecedented 4th term as POTUS. The inauguration for the 4th term was less grand this time around. Instead of at the Capitol, the ceremony was held on the South Portico of the White House. The reason for the difference in ceremonies was because the U.S. was at war and it was Roosevelt's 4th time. Business as usual. In that 1944 election, Truman was elected to the vice presidency. He was FDR's third vice president. John Nance Garner, a conservative Democrat from Texas, was elected and reelected with FDR in 1932 and 1936 and for FDR's 3rd term he had liberal Democrat Henry A. Wallace from Iowa as his running-mate. Wallace was so liberal in the minds of Democrats in 1944 that if he remained on the ticket it would harm FDR's chances of reelection. His 4th election was the closest of his four but he still pulled in over 50% of the popular vote. He ran against the young and popular New York Governor Thomas Dewey, who would run an even closer race four years later against President Truman. Had FDR passed away before January 20, 1945, Wallace would've been POTUS. In 1940, Wallace went from the head of the Agriculture Department to the vice presidency. After his term as vice president, he would return to FDR's (and remain with President Truman's) cabinet as the Secretary of Commerce. Wallace would eventually leave the cabinet and in the 1948 election run against Truman and Republican Dewey as the Progressive Party's candidate. He would come in fourth and with no Electoral Votes against third place finisher (and winner of some Electoral Votes) Dixiecrat Strom Thurmond. At the 1945 inauguration, Wallace swore-in the vice president-elect just as Garner had done for Wallace at the 1941 inauguration. Truman would be the vice president for only 82 days, before taking the Oath of Office.
Upon arriving at the White House and learning of the FDR's passing, Truman asked First Lady Eleanor Roosevelt "Is there anything I can do for you?" to which she replied "Is there anything we can do for you? For you are the one in trouble now." After he took the oath, he said of his new responsibility, "I don't know if any of you have had a bale of hay fall on you. Well, I feel like the sun, the stars and all the planets just fell on me."