Weber’s view has since fallen out of favor, but Brat, who studied at a Presbyterian seminary before pursuing a degree in economics, has tried to carry on an extreme variant of this tradition anyway. In his doctoral thesis at American University, “Human Capital, Religion and Economic Growth,” he argued that Protestant countries grew more quickly because they were particularly supportive of scientific exploration. The role of religion was “not large compared to other factors,” but ignoring it would “be a significant omission.” Over the years, he has grown only more convinced of his views. “The one source of economic growth is virtue,” he told The Richmond Times-Dispatch last year. “It is not property rights, not law or resources, but virtue.”

Brat’s political success suggests a fundamental evolution in the Republican Party. During the late 1990s, Senator Phil Gramm and Representative Dick Armey, former economics professors, played key roles in the government’s deregulation of the financial industry. Gramm helped write the Gramm-Leach-Bliley Act of 1999, which cleared the way for the emergence of financial supermarkets, like Citigroup, that offered banking and brokerage and insurance services. Armey, as the House majority leader, was a noted deficit hawk.

But neither of them identified closely with the Christian right. Free-market economists, after all, are explicit that companies are held accountable by customers, competitors and shareholders: They don’t need the government’s help, and they don’t need God’s either. Religious voters effectively ended Gramm’s bid for the presidency in early 1996, when he was upset by Pat Buchanan in the Louisiana caucus. And Armey, who left Congress in 2003, has continued to argue that some of the Christian right’s views are at odds with a libertarian commitment to individual freedom. “When the social conservatives and the economic conservatives work well together is when they work with a common resistance to the growth of the power of the state,” Armey said in 2010. “My point is very simple: You live a righteous life, you’re an encouragement to other people; use the state to impose it, and you’re a tyrant.”

But whereas the Republican Party was once a coalition of capitalists and Christians, it’s increasingly populated by people who profess belief in both. David E. Campbell, a professor of political science at the University of Notre Dame, has found a significant overlap between the Tea Party and the religious right. In 2006, Campbell and his collaborator, Robert D. Putnam, a professor of public policy at Harvard University, interviewed about 3,000 Americans. When most were interviewed again, in 2011, the professors found that the people most likely to identify with the Tea Party were those who previously wanted religion to play a large role in government. Campbell said that it made sense that people who came of age when the Republican Party was a coalition of those two things are now forming a generation that “is just going to believe in both things.”