So Truman was not expected to win but he won and this wasnt a political upset because????
American History: Truman Wins the Election of 1948
It definitely was a upset, you're right! My mother used to talk about that race a lot. Dad was for Dewey & ma was for Truman and when they found
out that Truman won they both were pleased Truman won. However I still don't think it was as big an upset as Trump beating Mrs. Clinton was.
I looked up the specifics of the 48 race & there was similarities to the 2016 election.
1) A Democrat talking point was that they lost Pa, Mich & Wis by only 70,000 votes & if they won those states Clinton would have won while:
Dewey lost Ohio, Cal & Ill by less than 60,000 votes with the margin of victory less than 1% in each state & with those 78 electorals Dewey would have won
2) Dewey because he won Ohio in 1944 over Roosevelt was so certain of Ohio that he didn't campaign there like we heard so many times that Mrs. Clinton
because Wisconsin had gone Democrat in the last 7 presidential elections similarly did not campaign there. Big mistakes by both.
I think Truman became the underdog early on because it was felt that he would be damaged by third parties both who historically voted Democrat.
The two third parties did not hurt Truman nearly as much as expected. Thurmond's Dixiecrats carried only four Southern states, a lower total than predicted.
Wallace's Progressives received only 2.4% of the national popular vote, well below their expected vote total and slightly less than the Dixiecrats, and Wallace
did not take as many liberal votes from Truman as many political pundits had predicted.
An interesting footnote:
As of 2019, this remains the last election in which Illinois and New Jersey have not voted for the same candidate.