When would Ike have switched Parties?

[Okay, maybe Mike Johnson is a competent parliamentarian.]

He wouldn't have. Ike had a genepool Plains-German dislike and distrust of the Democratic Party; the only reason he was seen as a potential Democratic substitute candidate in 1948 was that this was not commonly known at the time. I don't agree with the idea that he wouldn't have any issue with Bush or with Trump at all, but I think he would chart a course much closer to someone like Romney or Liz Cheney than to the Lincoln Project if he were alive and politically relevant today.

[Okay, maybe Mike Johnson is a competent parliamentarian.]

1996 : Buchanan

I think this is overcorrecting from the idea of Moderate Hero Sexgod Ike. Dole would have been plenty conservative for him.

[Okay, maybe Mike Johnson is a competent parliamentarian.]

For what it's worth, I believe Eisenhower was going to run as a Democrat if it looked like MacCarthur would get the Republican nomination.

That says way more about MacArthur than about Eisenhower.