A third party would cause conservatism to wander in the wilderness for years ...Do you think voting for a moderate to liberal Republican Candidate will keep Conservatives from wandering for years as well? A win by McCain changes the electoral formula. This will just make Conservatives wander inside the Republican Party where they are easier to ignore. Think about the Black vote for the Democrats. So reliable that they are easily ignored.
Remember that the Republican Party was formed from the ashes of the Whig Party.
A lot more room to wander in the wilderness than in the Tent.
Out of our previous "wandering in the wilderness" came the Reagan Revolution.