How do "the parties switched platforms" people explain Joe McCarthy?

[Benjamin Frank]

I don't think anyone is arguing that the parties completely switched, but both parties used to be much more ideologically diverse and have both liberal and conservative factions. There was a robust liberal wing of the GOP that was primarily based in the Northeast, along with a large contingent of conservative Democrats mostly from the South.

Now, most Northeastern liberals are Democrats and most Southern conservatives are Republicans.

A Conservative Republican Senator  voted against the 1964 Civil Rights act. And no, he was not Barry Goldwater.

It was a guy named Norris Cotton; who otherwise voted for the 1965 voting rights act.

He voted to end cloture though. There were other Republicans not from the South who voted in favor of the filibuster, which was really the more important vote.

The 6 Republicans were: Wallace F. Bennett (Utah), Barry Goldwater (Ariz.), Edwin L. Mechem (N.M.), Milward L. Simpson (Wyo.), John G. Tower (Texas) and Milton R. Young (N.D.). The following Democrats joined 18 from the deep South in voting against ending the debate: Alan Bible (Nev.), Robert C.Byrd (W.Va.), Albert Gore (Tenn.), Herbert S. Walters (Tenn.) and Carl Hayden (Ariz.), dean of the Senate, who had never voted for cloture

https://library.cqpress.com/cqalmanac/document.php?id=cqal64-1304621

[Benjamin Frank]

I don't think anyone is arguing that the parties completely switched, but both parties used to be much more ideologically diverse and have both liberal and conservative factions. There was a robust liberal wing of the GOP that was primarily based in the Northeast, along with a large contingent of conservative Democrats mostly from the South.

Now, most Northeastern liberals are Democrats and most Southern conservatives are Republicans.

The Republicans also had quasi-socialist (in the Western world rather than Eastern world sense) figures such as Robert La Follette Sr, Fiorello La Guardia and Henry Wallace (before he became a Democrat). That's a political tradition that faded pretty much by the Second World War and swept up by FDR and the New Deal (hence Wallace being FDR's second Vice President). LBJ and the Great Society swept up much of the liberal tradition within the GOP, at that point led by Nelson Rockefeller and previously by the likes of Earl Warren and Thomas Dewey. From then on, most liberals within the GOP were as thus in a relative sense rather than in an absolute sense. Colin Powell's endorsement of Barack Obama in 2008 was perhaps the symbolic final nail for this tradition.

There were liberal Republicans up to the 1980s. To be sure not as liberal as the most liberal Democrats, but rankings groups like the ADA and the ACU had them much more liberal than conservative southern Democrats - mostly on the coasts Senators like Dan Evans of Washington and Mark Hatfield of Oregon.

I suppose the symbolic nail could be argued to be liberal New York Republican Senator Jacob Javits losing the Republican nomination to Alphonse D'Amato in 1980, which also heralded the Reagan Revolution. Javits ended up running on the Liberal Party line in New York and got about 11% of the vote, enough to split the vote and cause the election of D'Amato over Democrat Elizabeth Holtzman.