The two sides often come to the same issue for completely different reasons. The National Rifle Association, for instance, recently joined the American Civil Liberties Union on a lawsuit challenging the NSA’s surveillance programs. The NRA’s concern is that surveillance could be used to create a national gun registry—a fear that critics dismiss as conspiratorial—but whatever the motive, the ACLU is happy for the support.

But while a constituency might be there, no movement now exists to channel the energy bubbling up from the grassroots into real political power. Instead, the populist wings of the Left and the Right tend to organize themselves in parallel and have little interest in joining forces—at least publicly. “When it comes to grassroots organizing, you see different groups coming together on certain votes,” Kibbe said, “then going back to their respective camps when it comes time for politics.”

Mark Meckler cofounded the Tea Party Patriots, the movement’s largest umbrella group, but stepped down last year and joined with an unlikely ally, MoveOn.org founder Joan Blades, to facilitate “living-room conversations” among people with different political views. “There’s just a whole litany of issues where the people are on the same side, but the politicians and the media are working very hard to keep us apart,” Meckler said. He cited a trans-partisan skepticism of “bigness,” in terms of both government and corporate power, and especially when they team up. “You can go far right or far left, and you come full circle.”

Despite that convergence, Meckler said, it’s hard for organizations that have to cater to bases—often by beating up on the other side—to cross the political divide. He notes that the Tea Party Patriots would sometimes work with liberal groups on issues where they had common ground and even share resources, but always through back channels.