Yesterday, five leading Republican candidates participated in the Palmetto Freedom Forum, a serious debate on constitutional principles. Mitt Romney, Michelle Bachmann, Newt Gingrich, Ron Paul, and Herman Cain answered questions from Tea Party congressmen Jim DeMint and Steve King, and Princeton professor Robert P. George.

National Review Online has gathered reactions to the debate from notable conservatives; Acton director of research Samuel Gregg and senior fellow Marvin Olasky are among them. Gregg’s take-away is that American politics is shifting in two ways: first, constitutional conservatism is now seen as a winning message, and candidates are unafraid to disavow progressivism as a whole; and second, issues, particularly economic ones, once on the margins of political debate are now up for discussion in the mainstream.

Here is the full text of Gregg’s response.

If there was any theme linking the responses to the questions posed by Senator DeMint, Congressman King, and Professor George to five of the Republicans seeking their party’s nomination for president during today’s South Carolina debate, it was the need for America to return to its founding principles. Yes, there was substantive discussion of specific matters ranging from financial regulation to immigration. But again and again, most of the candidates articulated the principles—and subsequent policies—of constitutional conservation.

Politically this makes sense, because it helps to integrate American conservatism’s fiscal and social wings. But it also reflects many Americans’ consciousness that the last four years have seen an acceleration of a long drift away from the best of the American experiment. So whether it was different candidates quoting Jefferson at length, or Ron Paul and Robert George discussing the 14th Amendment’s finer details, evidence mounted that constitutional conservatism is going to be a major reference point for whoever ends up running against President Obama in 2012.

The second aspect of the debate worth underscoring is how issues once considered marginal to mainstream politics are ing central. It’s no longer just Ron Paul talking about the need for sound money. The economic downturn and the failure of interventionist policies have turned the Fed and fiat money into live issues that no conservative candidate for office can ignore. Ben Bernanke—you’re on notice.