Why did the GOP loose Congress in 1948?

[darklordoftech]

Truman was an incumbent, so how did his party regain Congress?

[Southern Senator North Carolina Yankee]

The Democrats under Truman, rallied strong support from labor unions, from younger (Greatest Generation) voters (who were much more diverse ethnically speaking) and from African-Americans thanks to his desegregation of Army and the DNC adopting the pro-Civil Rights plank.

Dewey avoided specific issues and thus Republicans became defined by inaction on a range of issues in Congress like Civil Rights, as well as the action taken to curtail unions.

Because Republicans were not a national party and had to depend on the Northeast and Midwest, this meant that 1946 was built on a lot of urban seats, with a lot of exposure to the above hostile demographics that were demoralized in 1946 or disappointed with Truman's performance thus far. For instance Republicans won every Philly district in 1946 and lost all but two of them in 1948.

[One Term Floridian]

The GOP clearly had no idea how to run a congressional majority after nearly two decades in the minority; Truman’s running against the “do-nothing” GOP Congress was actually quite clever because it rallied back the New Deal majority to vote for Democrats up and down the ballot.

[RINO Tom]

From the forming of the New Deal Coalition to the GOP finally cracking the Democratic stranglehold on the South (a slow, multi-factor process), there just weren't that many loyal Republicans in the GOP fold when compared to the Democrats' voter base.  The GOP gained Congress by winning seats in states like Missouri, New York and Massachusetts, and this only got them a 6-seat advantage; I think they simply benefited from fatigue and the national environment.  By 1948, Republicans lost seats in a plethora of traditionally Democratic states that Truman won, such as Oklahoma, Kentucky and West Virginia.

I'm no expert on the period, but it seems that until the 1950s and especially the 1960s, the GOP needed perfect conditions to put up a fight.

[Orser67]

Yeah, it's pretty striking that Democrats picked up 75 House seats and 9 Senate seats in a year where Truman won by about 4 points. Not really disagreeing with what anyone else has said, but imo it can largely be explained as a post-wave correction after really strong GOP years in 1946 (R+55 in the House) and 1942 (R+9 in the Senate) during a period of long-term Democratic dominance in Congress.

[TheElectoralBoobyPrize]

Split-ticketing was still pretty rare then. I imagine most third party presidential voters voted Democratic for Congress. The Republican share of the House vote is pretty close to what Dewey got.