Santorum, on the policy front, often takes the Pat Buchanan, Ross Perot route, calling for less immigration and protection of U.S. manufacturers. The danger with big-government populism is (a) it usually corrupts over time into big-government corporatism, and (b) Democrats can always go bigger on the big-government front.

A free-market populist agenda could include a war on corporate welfare, tax simplification, a payroll tax cut, clearing away regulatory burdens to sole practitioners and small businesses, and reforming safety net programs so that they ensnare fewer and empower more.

But when Santorum talks about helping the working class and looking out for those who are struggling, he makes a point that’s crucial: “I almost feel uncomfortable talking about, ‘Well, we need to do that to win.’ ” Santorum told me at the recent Southern Republican Leadership Conference. “We need to do that because it’s the right thing for America.”

Caring for those who are struggling, stripping the insiders of their political privilege, and ending the government programs that hurt people — these are things we have a moral obligation to do. If it does nothing else, Santorum’s campaign will hopefully convince Republicans to take up this effort.