The ongoing feud inside the Republican Party produced another casualty Wednesday when the chairman of the influential House conservative caucus fired his top staffer amid allegations that he undermined some GOP lawmakers in an alliance with conservative advocacy groups.

Rep. Steve Scalise (R-La.), chairman of the Republican Study Committee, told reporters that he fired Paul Teller, the RSC executive director, because he no longer had the “trust” of lawmakers. “We all rely on staff, but we have to have the full trust of our staff. Unfortunately, that’s no longer the case,” Scalise said. Teller did not respond to an e-mail seeking comment.

According to GOP aides familiar with the decision, the ouster came after Scalise learned this week that Teller had been working with outside conservative groups against the two-year budget deal that House Budget Committee Chairman Paul Ryan (R-Wis.) and Senate Budget Committee Chairman Patty Murray (D-Wash.) unveiled Tuesday night.

Scalise remains undecided on the matter, but large numbers of the RSC (representing more than 160 Republicans) are expected to support the legislation, while a large bloc is expected to oppose it. The legislation would increase the spending limit for federal agencies by about $63 billion over the next two years, offset by spending cuts and increased fees of $85 billion over the next decade.

Some conservatives, such as Rep. Jim Jordan (R-Ohio), Teller’s former boss as the RSC chairman in 2011 and 2012, oppose the deal for going above those spending limits without getting a broad reform of entitlement programs. Rep. Kevin Brady (R-Tex.), a veteran RSC member, described it as a “solid agreement” because the savings offsetting the increased spending are legitimate. “The more I dig into it, the better it gets,” Brady said.

Jordan called Teller a “good guy” but said that his firing was justified. “I completely support the chairman,” he said of Scalise’s move. Scalise sought and received the support of all the former chairmen of the powerful caucus in pushing Teller out.

One GOP aide familiar with the decision said that Teller had even worked with outside conservative groups to get them to pressure a few dozen of the most conservative Republicans not to support a “clean” funding resolution at the minimum level for the rest of the year — believing that doing so would provide full funding for President Obama’s health-care law for the remainder of the fiscal year.

Almost every member of the RSC has given up on the effort to defund the Affordable Care Act, a plan that they originally pushed in the fall that led to the 16-day shutdown of the federal government in October. Teller did not want to give up that fight.

This was not Teller’s first clash with RSC members. In late July 2011, as GOP leaders tried to craft an alternative plan to lift the debt ceiling, one of Teller’s aides e-mailed conservative groups asking them to send statements to the Capitol “every hour of the day” in opposition to the plan. Rank-and-file Republicans were furious and at one point chanted “fire him” about Teller in a meeting.

“When I ran, I ran to restore the RSC as a member-driven organization,” Scalise said Wednesday, explaining his decision.