IN an election year, some outcomes are unpredictable, but one is inevitable: Conservatives will fight among themselves. They will accuse one another of having abandoned conservative ideals, admonish each other for having mistaken the essence of conservatism, and abjure their erstwhile fellows for having sold out principle for expediency.  Such struggles are not the product of a temporary historical juncture—they are built into the very structure of conservatism, and perhaps American conservatism more than any other.