Iowa Rep. Steve King — a tea party favorite, himself, and close friend of Bachmann — acknowledged that he hasn’t heard a peep out of the House Tea Party Caucus in the past few months.

“The reason for that is Michele Bachmann leads the Tea Party Caucus, and she’s almost 100 percent campaigning for president right now,” King said in a phone interview. But he argued the group carried clout in the House and said it would continue to function whether Bachmann is in Washington or in Iowa.

Members of the House often organize into caucuses to have a greater voice in floor debates and to extract concessions out of their party’s leadership. But in the House, there already is an established caucus of conservatives — the Republican Study Committee, which boasts a roster of more than 170. And in the Senate, there’s the conservative Steering Committee that has a hired staff that promotes policy ideas.

“I didn’t want to have to be in a caucus within a caucus,” said Sen. Marco Rubio (R-Fla.), a tea party favorite who is a Steering Committee member but declined to join the tea party group.

Critics say both the House and the Senate Tea Party caucuses are simply designed to allow lawmakers to attach their names to them so they can point to their work on behalf of the grass-roots movement when they speak with voters back home. The lack of activity, they say, confirms that suspicion.