Finally in the 1960s, he left the party to join the Republicans, presumably incensed over not being issued the treasured N-Word Pass.
I won't defend Thurmond on race, but a huge part of the 1964 story and his switch is that the Democrats were completely awful on foreign policy, and getting worse on non-racial domestic politics.
Thurmond was a highly decorated
WW2 combat pilot, holding the rank of Major General in the Army Reserves when he retired. (The Air Force proper wasn't formed until after WW2.) The Democrats under Kennedy had just fucked up the Bay of Pigs invasion, and Johnson was getting involved with Vietnam. Aside from civil rights, in the 1960s the Democrats were quickly moving left on more things like welfare, the regulatory state, nuclear power, etc.
When Thurmond left the Democratic party, he gave a televised speech explaining why. It is extremely hard to find copies of that speech, which suggests it doesn't make the Democrats of his time look very good. But there was some pre-coverage from
the New York Times. It seems to match up with contemporary descriptions of the actual speech, including the NYT's own
followup.
Sources here said his television speech would include a strong attack against the Democratic party for the United States role in the war in South Vietnam and for the failure of the Bay of Pigs invasion of Cuba in 1962.
Mr. Thurmond has previously accused the Defense Department of a “no‐win policy."
...
A much‐decorated hero during World War II, Mr, Thurmond is a major general in the Army Reservea. Mr. Goldwater has a similar rank in the Air Force Reserves.
Both Senators have opposed the Administration on such matters as civil rights, medical eare for the aged, the nuclear test ban treaty and the antipoverty program.
In the 1960 campaign Mr. Thurmond said the Democratic platform was “a blueprint for a welfare state and an end to individual liberty and dignity in the United States.”
From the NYT post-speech
article:
“The Democratic party has abandoned the people,” he asserted. “It has repudiated the Constitution of the United States; It is leading the evolution of our nation to a socialistic dictatorship.”
Senator Thurmond urged other Southerners to join him in a fight to elect Senator Goldwater and to make the Republican party ‘a’ party which supports freedom, justice and constitutional government.”
They mention Goldwater because Thurmond became a supporter of the libertarian Goldwater around the same time. Thurmond was an outright segregationist, but many conservatives and libertarians opposed the Civil Rights Act because it had authoritarian enforcement and cracked down on personal freedoms. It destroyed the last remaining balance of federalism in pursuit of equality (and SCOTUS went along with it).
In a speech in Spartanburg in 1960, Mr. Goldwater said there was not enough difference between Mr. Thurmond as a South Carolina. Democratic conservative and a Republican conservative “to put a piece of paper between them."
Sound like any other cross-party dynamic that may have happened in the last year?