The GOP seems to have less of an immigration problem than an emigration problem, which I would characterize as "bright flight." Much as middle-class whites took flight from inner cities' "color problem" in the postwar era and well beyond, both chronologically and geographically, intelligent Republicans are fleeing their party, philosophically and formally, at what appears to be an accelerating rate. (Just to be clear, I am in no way equating the latter's intelligence with the former's bigotry.)
I should emphasize appears (it's the ineradicable skeptic in me). Perhaps it has merely become fashionable for the independently conservative-minded to go public with their loss of faith by hammering their political theses in explosions of alienation on their pious brethren's doors. I can't say, for sure. This particular flight is less amenable to precise quantification than, say, the 1960s' variety. Nonetheless something is happening; it is an observable, empirical, and utterly delightful phenomenon.
The latest émigré is one Michael Stafford, a lawyer, Delawarean and now former officer of his state party. "Today ... I am a registered Republican no longer," he announced yesterday, having had quite enough of the GOP's "dangerous and virulent form of political rabies," "Its fevered hallucinations involv[ing] threats from imaginary communists and socialists," evil conspiracy theories about climate change, "notorious birther[ism]," and "indefensible" economic policies.
For Stafford, the final straw: "few figures in the GOP have the courage to confront them.... Perhaps, one day, a reformed and responsible Republican Party will reemerge." Stafford is Jeb Bush's base; small for now, but snowballing.
I realize that in "bright flight" there's a touch of unwarranted graciousness. The above-referenced gentlemen--and others--have actually been a bit slow on the uptake; conservatism's Sullivans and Frums and assorted perceptive others have been mourning the death of prudence for years. How any intelligent, well-informed Republican could have missed the warnings of these five-alarm observers--or even worse, missed the plain, tangible evidence of the party's intellectual rubble all around them--is beyond customary partisan comprehension. Heroic--if tragic--loyalty, maybe? Or, could be, they were just frogs in heating water. It's hard to know.
What is knowable, however--roughly quantifiable in appearances, anyway--is that Republican self-identification is down, while independent self-identification is up. And in this occurance, causation would seem to speak to correlation: more and more thoughtful, traditional conservatives are simply too embarrassed to even call themselves Republicans, and they're taking flight.