Last week, the vote to bring Trade Promotion Authority and Trade Adjustment Assistance to the House floor almost failed, with most of the chamber’s Democrats voting no. But 34 Republicans also snubbed their party’s leadership. Three of the mutineers were members of the House Republicans’ “whip team,” meaning they were supposed to be drumming up support for Speaker John Boehner instead of publicly bucking him. They were subsequently booted from the team.

Like many Republicans who voted against TPA, those three, Reps. Cynthia Lummis, Steve Pearce, and Trent Franks, are members of the House Freedom Caucus, a young conservative group that has variously been described in news accounts as “an upstart group of hardline Republicans,” “far-right renegades,” and “a formalized ‘hell no’ caucus.” The Freedom Caucus has played a central role in a number of challenges on the House floor that have stymied the Republican leadership, often voting with Democrats on measures that push Boehner and his colleagues to make last-minute accommodations or accept failure on legislation.

These internecine battles have riled other Republicans, who place much of the blame for the House GOP’s difficulties on the caucus. The secrecy of the invitation-only group adds to the frustration. The Freedom Caucus does not have a website, its meetings occur behind closed doors, and it has not released a full list of members—although several, including Virginia Rep. Dave Brat, have publicly boasted about their membership.

Founded in January by Reps. Jim Jordan, Scott Garrett, John Fleming, Matt Salmon, Justin Amash, Raúl Labrador, Mick Mulvaney, Ron DeSantis, and Mark Meadows, the group’s mission statement says that it “gives a voice to countless Americans who feel that Washington does not represent them.” It proclaims fealty to “open, accountable and limited government, the Constitution and the rule of law, and policies that promote the liberty, safety and prosperity of all Americans.”

As Jordan, the current chairman, pithily explained to RealClearPolitics, “Republicans aren’t doing what they said they were going to do. So, our job is to do what we said we were going to do. And that’s what the Freedom Caucus is designed to do: remember those middle-class families and do what we said we were going to do.”

Labrador told RCP that he and his colleagues founded the Freedom Caucus in order to craft and propose policy solutions that could unify conservatives.

“Several of us decided that it might be better for us to have a small, nimble group that could take ideas to leadership,” he said. “We could work in a positive direction: instead of just being against things, we could tell them how we could do more things if they worked with us in a positive fashion.”

The nascent group considered participating in the 170-member Republican Study Committee, which for decades has shaped House GOP policy, as a way to achieve these goals, but they eventually decided to work outside of the “existing structures,” Labrador said. (Jordan chaired the study group in the 112th Congress and remains a member.) On Jan. 12, 37 representatives attended the Freedom Caucus’ inaugural meeting in the Cannon Office Building. Two weeks later, the group released its mission statement, and Labrador announced that he was leaving the RSC.

Yet despite how the group’s members portray their purpose, its secrecy is a source of tension for other Republicans. “They always meet in secret,” California Rep. Devin Nunes said in an interview. “And nobody knows who’s in their group.” Jordan estimated there are 40 members and added that most of them are willing to acknowledge their membership, but said that the caucus “just made a decision” not to formally release the names.

Several other representatives have already been confirmed as Freedom Caucus members, including Reps. Tom McClintock of California, Matt Salmon of Arizona, and Curt Clawson of Florida. Another, Rep. Jeff Duncan of South Carolina, resigned from the Republican whip team in February with DeSantis. Most of these members are fairly new to Capitol Hill. Although Garrett has been in Congress since 2003 and Jordan since 2007, few others were in office before 2009.

On Feb. 27, caucus members were among the 52 Republicans who voted against a three-week extension of Department of Homeland Security funding in opposition to President Obama’s executive amnesty for immigrants, joining 172 Democrats to block the measure. More than two dozen of those same representatives counted among the 47 Republicans to vote against the USA Freedom Act on May 13. Although that bill overwhelmingly passed, Labrador and Amash explained at a press event later that month that they were concerned it violated Fourth Amendment protections against unreasonable searches and seizures.

The debate over government surveillance that culminated in the USA Freedom Act underscores the Freedom Caucus’s main grievance against the House leadership, which according to group members ignores or discards the ideas of many of its rank-and-file members.

Jordan offered the example of an amendment offered by Reps. Thomas Massie, Jim Sensenbrenner, and Zoe Lofgren (a Democrat) that included measures to prevent the government from accessing private data without a warrant and from forcing companies to assist in the surveillance of clients. The measure passed 293-123 in the House in June 2014, but it never moved to the Senate because it was not included in the CRomnibus funding bill last fall (which overrode other spending legislation). An identical measure eventually passed the House on June 11 this year as an amendment to the Department of Defense Appropriations Act.

“We have a problem right now in the House that we have a very top-down management style, that only the idea of the top people, the leadership, is heard,” said Labrador. “It doesn’t matter if you’re talking to conservatives, or moderates, or whatever you want to classify them as in the House of Representatives. They feel like they have not been empowered by the process, like they’re not equal in respect and rank as everybody else.”

Critics argue that by opposing their party on divisive procedural votes, the House Freedom Caucus essentially helps the Democrats. “When you vote against rules, you hand the House over to Nancy Pelosi,” said Nunes. “So really they might as well just join the Democratic caucus, because that is what they’re doing.”

On Tuesday morning, John Boehner chastised lawmakers in a closed-door Republican meeting for opposing him on the TPA rule vote that resulted in the whip team shake-up. “We’ve worked hard to stay in the majority and I expect our team to act like a team,” he told reporters afterwards. “And I, frankly, made it pretty clear I wasn’t very happy.”

Talking to Fox Business Network’s Neil Cavuto on Wednesday, Jordan acknowledged that Boehner yelled at members in the meeting, but added that the leadership’s efforts to negotiate with Democrats were counterproductive and inconsistent with their promises to voters: “Instead of yelling at us, why doesn’t he just work with us? I mean, they tried working with the Democrats, and they saw how that turned out—they left them standing high and dry … Was [TPA] a key issue in last fall’s campaign? I don’t think so.”

An aide familiar with the negotiations disputed the claim that House leadership did not engage with Freedom Caucus members and stated that in the debates surrounding TPA, the Republican leadership had held conversations with Freedom Caucus members. The aide added that members of the Freedom Caucus made negotiations difficult by sticking to unrealistic demands, which forced GOP leaders to work with Democrats.

Members of the House Freedom Caucus see it as a deliberative body where every voice can be heard and the group adopts a position through debate. According to Jordan, the Freedom Caucus is now focused on ending the Export-Import Bank. And if the past months are any guide, when the group adopts a stance on an issue, it becomes a formidable and even intransigent bloc in the Republican conference.