“This really does change everything,” Romney said.

His appearance on the television risers elicited chants of “Mitt, Mitt, Mitt!” He meandered over to row of reporters to reiterate that his focus was on helping Republicans win seats in 2010 not on the presidential election in 2012. Excitable Republicans are already talking up Brown as a viable vice presidential candidate down the line. But it’s hard to imagine anyone competing with Romney, let alone a fellow Bay Stater, for the middle-of-the-road Republican vote…

The role that those groups played in Brown’s victories will continue to roil the Republican Party. The support of groups like Tea Party Express is either a sign of the anti-government movement’s maturation—only a few months ago they were chasing a similarly moderate Republican named Dede Scozzafava out of a congressional race in upstate New York—or a sign of the populist groups’ utter lack of focus. Like the tea partiers, Brown avoided the Republican label, favoring talk of “independent leadership” and being an “independent voice.” Unlike the tea party movement, Brown’s distance from the Republicans was an effort to win votes on the left, not the right. It will be interesting to see whether the tea party crowd’s enthusiasm for Brown—so strong down the home stretch of the campaign—will remain after the victory parties die down.