Tea party activists always worked alongside like-minded conservative organizations, but they failed to capitalize on the anti-Obama momentum in 2009 and 2010 to build their own infrastructure and war chests. That means national groups like American Majority, the Club for Growth and the Koch brothers-linked Americans for Prosperity are essentially in the position to determine if GOP incumbents face serious primary challenges…

The tea party “is in disarray,” said Erick Erickson, the editor of RedState, a blog that helped crystallize the fiscally conservative ethos of the populist movement. Going forward, tea partiers will “either be within the conservative movement as part of that movement or they won’t be effective.”…

“The grass roots are a lot more cynical than they were in 2010,” said Jenny Beth Martin, co-founder of Tea Party Patriots, a Georgia-based nonprofit that fashioned itself as an umbrella coalition of local tea party groups. “They only want to take actions that are going to have real impact, and not just something that is going to make noise for the sake of making noise.”

Tea party activists may have “missed the moment” to build a more enduring structure that could help boost primary challenges to Republican congressional incumbents deemed insufficiently conservative on fiscal issues, said Ned Ryun, president of the grass-roots organizing outfit American Majority, which trained local activists and offered them grants and assistance in setting up their own groups.