Leaders of more than 70 Tea Party groups in Indiana gathered last weekend to sign a proclamation saying they would all support one candidate  as yet undetermined  in a primary challenge to Senator Richard G. Lugar, the Republican who has represented the state since 1977.

They are organizing early, they say, to prevent what happened last year, when several Tea Party candidates split the vote in Republican Senate primaries, allowing the most establishment of the candidates to win with less than 40 percent.

The meeting in Sharpsville was hardly the exception. Just three months after the midterm elections, Tea Party organizers are preparing to challenge some of the longest-serving Republican incumbents in 2012.

In Maine, there is already one candidate running on a Tea Party platform against Senator Olympia J. Snowe. Supporters there are seeking others to run, declaring that they, too, will back the person they view as the strongest candidate to avoid splitting their vote. In Utah, the same people who ousted Senator Robert F. Bennett at the state’s Republican convention last spring are now looking at a challenge to Senator Orrin G. Hatch.