“I think that there will be a primary challenge,’’ said Christen Varley, president of the Greater Boston Tea Party. “There’s enough of an underground movement in the Tea Party movement as seeing him as not being conservative enough. There probably will be multiple people who attempt to run against him.’’

Varley said it is too early to name a possible opponent, and she acknowledged that Brown’s campaign war chest and statewide organization would probably be enough to fend off an opponent. But if Brown has to devote energy and resources to a primary campaign, it could put him at a greater disadvantage in a general election in which Democrats will be fighting hard to reclaim a seat they consider theirs…

“I have talked to people who have said unless he turns around on some of these issues that they don’t like, they’re not going to work for him again,’’ said Matt Clemente, the Massachusetts director for the Tea Party-affiliated group FreedomWorks, which has 12,400 members in the Bay State. “We’re going to watch very closely over the next year and a half . . . and see if he’s going to be the ally that everyone had hoped it was going to be.