House Democrats are preparing themselves for a caucus in 2027 that is significantly more outspoken and left-wing than the one they have now.Why it matters: It wasn't all that easy to integrate the four-member "Squad" into the Democratic fold. Now party leadership is going to have to contend with a much larger cohort of rabble rousers.Rep. Steve Cohen (D-Tenn.) predicted "it will be difficult" to rein in these newly elected democratic socialists: "I think people that follow that [ideology] will cause problems."Said another House Democrat: "People are electing candidates who say they're going to fight, not solve problems. What they're going to get is fights.""If they're actually serious legislators, then they going to have to be able to work with people," a third House Democrat said. "If not, then they'll just be the Freedom Caucus of the left."Driving the news: The number of Democratic Socialists of America (DSA) members in Congress is set to more than double following the New York primaries on Tuesday.State Assembly member Claire Valdez won the seat of retiring Rep. Nydia Velázquez (D-N.Y.) and activist Darializa Avila Chevalier unseated Rep. Adriano Espaillat (D-N.Y.).They join Pennsylvania state Rep. Chris Rabb, a DSA member who won the primary to succeed Rep. Dwight Evans (D-Pa.) last month, along with Reps. Alexandria Ocasio-Cortez (D-N.Y.) and Rashida Tlaib (D-Mich.).Zoom out: Factoring in left-wing candidates who are broadly aligned with the DSA, the numbers get even more daunting for the party establishment.The primary wins of now-Rep. Analilia Mejia and Adam Hamawy in New Jersey, the Rev. Frederick Haynes III in Texas, Randy Villegas in California and Matthew Dunlap in Maine were all major victories for the left.Several other progressives are seen as well-positioned to potentially unseat incumbent House Democrats: Mai Vang and Angela Gonzales-Torres in California, Melat Kiros in Colorado, Elijah Manley in Florida, Cori Bush in Missouri, and Donavan McKinney in Michigan.What we're hearing: These candidates are already communicating and coordinating with each other in various text chains, with several telling Axios they will plan continue to work together as a bloc in Congress."We have to deliver something, and whether it's being a part of the Congressional Progressive or maybe doing our own thing, I don't know, we have to just push and people have to see us fighting," said McKinney.Said Vang: "As a new cohort of progressive elected, we have leverage ... so Hakeem Jeffries needs to be aligned with that. And when I get to the halls of Congress, I do look forward to organizing with my colleagues."The other side: Some in the Democratic establishment fear this will be a repeat of House GOP leadership's struggles with the Freedom Caucus in 2023 — especially if Democrats have a slim majority in the House."The 'Squad' at its largest prior iteration was probably about 10" members, a fourth House Democrat told Axios, "so now if that number is 25 ... you could sink the boat. You could say, 'Unless you do everything the way I want, I'm not going to be with you.'"Said a fifth House Democrat: "Especially with a narrow majority you're going to see a big tug-of-war between [establishment] Democrats and socialists."A sixth House Democrat said the dynamic "definitely could present challenges. Leadership will matter a lot."Yes, but: Democratic leadership is largely projecting confidence that, when these lawmakers get into office, they can ultimately be brought into the fold."We'll ... have conversations and build relationships with them," House Democratic Caucus Chair Pete Aguilar (D-Calif.) told reporters at a press conference, saying he wants them to "be successful for their constituents."Jeffries "knows how to pull people together," said Rep. Debbie Dingell (D-Mich.), another member of Democratic leadership, noting that Ocasio-Cortez "has been a part of our caucus for a long time."