The Midwest begins on the western slopes of the Allegheny Mountains, around Rick Santorum’s Pittsburgh, birthplace of the Ohio River, the original highway into the Midwest. Pittsburgh fueled the Whiskey Rebellion of 1794, an early eruption of Western resentment of the overbearing East, which taxed the whiskey that Westerners made from their grain. Santorum the Midwesterner, after victories in Iowa, Minnesota and Missouri, is wagering more of his political capital on the region.

Rather than wait for the congenial calendar of Super Tuesday (March 6), featuring five culturally conservative states (Georgia, Tennessee, Virginia, Oklahoma, Idaho), he is contesting Michigan, which votes Tuesday, and Ohio. But instead of keeping his Rust Belt focus on his blue-collar roots and economic program for reviving manufacturing, he has opened multiple fronts in the culture wars.

By doing so — questioning much prenatal testing, disdaining Barack Obama’s environmentalism as “phony theology,” calling involvement of even state governments in public education “anachronistic,” reiterating that abortion should be illegal even in cases of rape and incest, explaining the proper purpose of sex (procreation) — Santorum has eclipsed Newt Gingrich, his rival for the support of social conservatives. But in doing so Santorum has made his Catholicism more central and problematic in this nomination contest than Romney’s Mormonism has been.

The problem is not that the phenomena that trouble Santorum are unserious. The use of prenatal testing for search-and-destroy missions against Down syndrome and other handicapped babies is barbaric. Obama’s stealthy pursuit of a national curriculum for kindergarten through 12th grade is ill-advised and illegal. And no domestic problem — not even the unsustainable entitlement state — is more urgent and intractable than that of family disintegration.

The entitlement state can be reformed by various known — if currently politically impossible — policy choices. But no one really knows the causes of family disintegration, so it is unclear whether those causes can be combated by government measures.

We do know the social pathologies flowing from the fact that now more than 50 percent of all babies born to women under age 30 are born to unmarried mothers. These pathologies, related to a constantly renewed cohort of adolescent males without fathers at home, include disorderly neighborhoods, schools that cannot teach, mass incarceration and the intergenerational transmission of poverty. We do not know how to address this with government policies, even though the nation has worried about it for almost 50 years.

In 1965, Daniel Patrick Moynihan, then in President Lyndon Johnson’s administration, published his report on the black family’s “crisis,” which was that 24 percent of black children were then born to unmarried women. Today, 73 percent are. Forty-one percent of all children are now born to unmarried women.

Moynihan, a social scientist in politics, proposed various family policies but also noted this: When the medieval invention of distilling was combined with Britain’s 18th-century surplus of grain, the result was cheap gin — and appalling pockets of social regression. The most effective response to which was not this or that government policy, it was John Wesley — Methodism. Which brings us back to Santorum.

He is an engagingly happy warrior, except when he is not. Then he is an angry prophet of a dystopian future in which, he has warned, people will be “holed up in their homes afraid to go outside at night.” He has the right forebodings but might have the wrong profession. Presidential candidates do not thrive as apostles of social regeneration; they are expected to be as sunny as Ronald Reagan was as he assured voters that they were as virtuous as their government was tedious.

Today’s Republican contest has become a binary choice between two similarly miscast candidates. Mitt Romney cannot convince voters that he understands the difference between business and politics, between being a CEO and the president. To bring economic rationality to an underperforming economic entity requires understanding a market segment. To bring confidence to a discouraged nation requires celebrating its history and sketching an inspiring destiny this history has presaged.

Romney is right about the futility of many current policies, but being offended by irrationality is insufficient. Santorum is right to be alarmed by many cultural trends but implies that religion must be the nexus between politics and cultural reform. Romney is not attracting people who want rationality leavened by romance. Santorum is repelling people who want politics unmediated by theology.

Neither Romney nor Santorum looks like a formidable candidate for November.

georgewill@washpost.com