Alternate History: In 1960 Rockefellar defeats Smathers.

[bhouston79]

This scenario begins with center-left Republican Senator from the state of New York, Nelson Rockefellar, winning the Republican nomination and the segregationist southern Senator from the state of Florida, George Smathers winning the Democratic nomination.  In the general election that follows, Rockefellar wins handily as Senator Smathers is able to unable to win any states outside of the South.  Here are the election results:

Electoral Vote

Rockefellar  399
Smathers    138

Popular Vote
Rockefellar   56 %
Smathers     43 %

Following this election, Rockefellar fights for and finally succesfully passes the 1964 Civil Rights act toward the end of his term in the runup to the 1964 Presidential election.  What happens next.  Do the Republicans become the progressive party for generations to come?  Or do Conservative Republicans revolt against Rockefellar?  What about the Democratic party?  How do the next 4 decades or so play out?

[Lincoln Republican]

President Rockefeller would be renominated by the Republicans without opposition, or at least, with only token opposition, in 1964.  Rockefeller would go on to win the 1964 election by an impressive margin.

For a decade at least, the Republican Party would certainly be more progressive, but clearly, the party would still have a sizeable conservative element in it.

I would not call it a revolt, however, it is likely that the Republicans would have nominated a more conservative candidate than Rockefeller for the 1968 election.  The Democrats would likely take the White House in 1968.