Santorum’s electoral advantage is sociological: His common-man, working-class sensibility would be highly appealing to battleground-state Reagan Democrats. His fundamental problem is ideological: He’s a deeply committed social conservative in a year when the country is obsessed with the economy and when conservatism is obsessed with limited government. Republicans, after all, swept the 2010 election on economic concerns and opposition to big government. The Tea Party revolution was not about gay marriage. Which is why so much Tea Party fervor attaches to Paul.