I’m more curious why he was considered doomed to defeat in 1948 when the economy was good and we weren’t in Korea yet. Was it just Democratic fatigue and/or the fact that Truman lacked Roosevelt’s charisma?
I agree with all the above comments on your question. Keeping in mind the backdrop of minor parties having won a significant share of the PV and EV in both 1912, and 1924, and that Blacks were still considered a reliably Republican constituency (even though they had voted Democratic in 1936, 1940, and 1944), in the end I think Truman won because (1) the Henry A. Wallace vote was smaller than expected (this didn't save Truman from defeat in NY, but probably got him OH and CA); (2) the Dixiecrat vote was not as great as feared (Truman comfortably won GA, NC, TN); (3) Blacks continued to voted strongly Democratic (80-85% I've read), largely because of their concern that, were Truman to lose, no Democratic politician would ever defy the South again; the Black vote probably carried Truman to victory in IL and OH, maybe even CA.
