Jim DeMint’s decision last December to leave the Senate to become president of the Heritage Foundation produced a mix of shock and hand-wringing in political circles. The shock involved some possibly quaint thinking about political power: DeMint was abandoning the lofty heights of the Senate—“long considered the pinnacle of power and influence in American politics,” as The Washington Post’s Chris Cillizza put it—to immerse himself in the world of policy research.

The hand-wringing, on the other hand, involved some even more quaint notions about the think tanks at the heart of Washington’s ideas industry. DeMint was not a “serious scholar,” wrote the Post’s conservative blogger, Jennifer Rubin. By making him its leader, she said, Heritage “becomes a political instrument in service of extremism, not a well-respected think tank and source of scholarship.”

Both reactions, though, leave out a crucial component: money. DeMint, who reported virtually no assets on congressional disclosure forms, stood to get a significant raise by moving to Heritage. Outgoing Heritage president Ed Fuelner received nearly $1.2 million in 2011, according to the group’s tax filing. If DeMint gets the same compensation—and one expects he’ll get more—it would amount to a raise of about 700 percent from his $174,000 annual take as a senator.

Once upon a time, the only way for a pol to cash in like that was to leave elected office in order to become a lobbyist—a nice living, but one that carries with it a stigma that would likely kill any future ambitions for high office. By contrast, a gig at Heritage, the main voice of the conservative movement, could be a good launching pad for a potential 2016 presidential bid. Candidate DeMint could run as a man of ideas, not another pol out shilling for his donors.

The problem with that wholesome image—and the anachronistic thing about Rubin's lament over Heritage's potential loss of intellectual virginity—is that think-tanking and lobbying have come to look more and more alike. Just like lobbyists, think tanks can frame policy debates and generate political pressure—for the right price.