Quoted from The Limits of Reaganism at Debatable Land (we need to add this site to our Anglosphere category)
...the Cult of Reagan actually helps explain the mess the Republican movement finds itself in. It used to be that it was the left that specialised in writing dissenters out of the movement; these days, in America at least, that's become a conservative trait. The RNC debate was illuminating in this respect: in addition to passing the Reagan litmus tests candidates were asked how many guns they own. And that was more or less it. Tick those boxes and you're a proper Republican; waver on either question and you're subject to suspicion.
It's this sort of blinkered thinking, this elevation of ideology above the messy business of winning elections that has helped condemn the GOP to minority status. A two party system in a nation of 300m people demands that each party be a broad church. Reagan recognised this; his successors seem to have forgotten it.
Read the whole thoughtful thing. You can get the other side of the argument from an emotional Michelle today. Debate is good. Certainty is never good.
Related: Could Obama's centrism drive the GOP out of business?