The Senate Conservatives Fund, which was already targeting Senate GOP Leader Mitch McConnell (R-Ky.) in his 2014 reelection bid, is now going after House Speaker John Boehner (R-Ohio) too.
In an e-mail to supporters, the group accuses Boehner of declaring "war on conservatives" by pushing for the budget compromise last week.
"What these leaders are doing to conservatives is no different from what the IRS got caught doing to them this summer," the group's executive director, Matt Hoskins, writes. "They're using their power to discriminate against people they see as a political threat."
Boehner last week criticized such groups in a way he hadn't before, saying they had lost "all credibility" for opposing the budget before it was officially introduced.
McConnell has also denounced these groups, accusing them of exploiting intra-party unrest for financial gain.
The Senate Conservatives Fund, which was once allied with ex-senator Jim DeMint (R-S.C.), does not say that it will target Boehner in a primary, as it is doing with McConnell, but it does urge its donors to contribute to five Senate candidates it has endorsed in order to fight back.
The House Republican who crafted the budget compromise, Rep. Paul Ryan (R-Wis.), has also found himself earning the opposition of these groups.
Despite the opposition, the budget passed in the House by an overwhelming margin. Republicans voted for it 169-62.