Things get tough, you disagree with five-ten percent of what the GOP does so you take your ball and go home, leaving the field open to the true enemy.
If folks disagree with just five or ten percent, then I say that's not a bad average. If folks disagree with a significant portion, then I say "don't vote for 'em."
There are a lot of reasons to vote for one political party, including, "we're not the other guy," which I'll accept. But to ask folks to vote for someone they don't agree with on a majority of issues is a fool's game. It's akin to the guy who says, "I'll not be held prisoner by my principles."