The Tea Party, the Club for Growth—the whole movement has succeeded in driving Republicans further to the right. Nuking a few moderates in primaries was only part of that—a great story for the horse-race media, but not something that would keep up as the GOP was purified. Think about the Tea Party as repeating (and perfecting) the strategy liberals used in 2006 and after, when online activists and unions banded together to beat Joe Lieberman in his U.S. Senate primary in Connecticut.

Lieberman ended up returning to the Senate. Liberals would oust only a couple more Democrats, like Maryland’s Rep. Al Wynn, in the next election cycle. But the Lieberman challenge drew a neon line in front of the party’s candidates: Oppose the Iraq War, oppose the surge, or you go nowhere. The party’s presidential candidates obeyed. Its next presidential nominee won the primaries in a squeaker in part because he, alone among the frontrunners, had always opposed the Iraq War.

Republicans seem to have figured this out. It’s increasingly likely that no incumbent Republican will lose a primary to a Tea Partier in 2012. The movement can consolidate its gains. Safe districts and the fear of primaries do more to keep Republicans straight than the occasional wins.