Ponnuru reviews "Why the Democrats are Blue"

Here.  He writes:

It would have required a lot of prescience to predict in 1965 that American politics, for so many decades based on economic divisions, would soon split over social issues and, especially, abortion. But not even a very prescient observer could have correctly predicted which party would take which side in the coming battles. On abortion, in particular, it looked obvious which way it would break: The Democrats were the party of Catholic Northerners and Southern whites, the party that believed in using the power of government to protect the weak; the Republicans were the party with historical ties to Planned Parenthood. . . .

It's an interesting story.  (Nutshell version:  Fred Dutton pushed out the old "party bosses", who were replaced by "Social Change activists".)