Paul instead touted his own bona fides.

“You know they have challenges, all the candidates. They haven’t challenged me for flip-flopping, so I am very proud of that,” Paul said.

Romney and Herman Cain are running atop the GOP field in recent polling. 

But Romney has faced challenges explaining his enactment of healthcare reform legislation containing an individual insurance mandate in Massachusetts while opposing Obama’s healthcare law, and has faced accusations of flips-flops on climate change and other issues.

Here are a couple paragraphs from Will’s assault on Romney:

Romney, supposedly the Republican most electable next November, is a recidivist reviser of his principles who is not only becoming less electable; he might damage GOP chances of capturing the Senate. Republican successes down the ticket will depend on the energies of the Tea Party and other conservatives, who will be deflated by a nominee whose blurry profile in caution communicates only calculated trimming.

Republicans may have found their Michael Dukakis, a technocratic Massachusetts governor who takes his bearings from “data” (although there is precious little to support Romney’s idea that in-state college tuition for children of illegal immigrants is a powerful magnet for such immigrants) and who believes elections should be about (in Dukakis’s words) “competence,” not “ideology.” But what would President Romney competently do when not pondering ethanol subsidies that he forthrightly says should stop sometime before “forever”? Has conservatism come so far, surmounting so many obstacles, to settle, at a moment of economic crisis, for this?