What a relief it must have been for Kevin McCarthy to finally pull it off. To bask in the ovation of his party. To bang the long-coveted gavel. To see it in gold letters above the door to his office: SPEAKER OF THE HOUSE. KEVIN MCCARTHY. It took extraordinary concessions, fifteen humiliating rounds of voting, and an intervention from Donald Trump himself. But in the end, the California Republican saved himself the greater embarrassment of another failed speakership bid—and landed the job he’s been lusting after for almost a decade now. “It’s not how you start, it’s how you finish,” McCarthy said after taking the gavel Saturday. “And now we need to finish strong for the American people.”

“I think what you will see by having this now, we’ve worked out how to work together,” he said of the bruising battle over his bid.

Is that true? We’ll find out soon enough. As McCarthy heads into his first full week as House Speaker, he’ll immediately be put to the test: Before he can start investigating Hunter Biden and targeting “woke indoctrination” and all the other asinine endeavors he and his colleagues have vowed to take up, he’s going to have to pass the rules package governing how the House will operate under the GOP majority. And, given the dramatic forfeitures he made to his further-right foes in the Freedom Caucus to get elected, drumming up his full caucus’s approval for it might not be so simple.

As in the speakership vote, McCarthy can suffer only four defections within his party—and, already, one Republican member has said he’ll vote against the rules package, which includes measures making it easier to oust McCarthy as speaker and committee posts for Freedom Caucus members. “At the end of the day, you can’t let…the insurgency caucus take hold and dictate,” McCarthy ally Tony Gonzales told Margaret Brennan on CBS News’ Face the Nation Sunday, criticizing the transparency of the rules package and the proposed defense cuts it contains. The possible slash in defense spending could also be a sticking point for Nancy Mace, another McCarthy ally, who told Brennan she was having similar reservations about the package. “I am on the fence right now,” the Republican representative said Sunday, calling Matt Gaetz, the ringleader of the McCarthy opposition, a “fraud.” 

“We don’t have any idea what promises were made or what gentleman’s handshakes were made,” Mace said of the concessions McCarthy made to Gaetz and others in order to ultimately prevail on the 15th ballot last week. “We just have no idea at this point. And it does give me quite a bit of heartburn, because that’s not what we ran on.” 

It’s unclear whether Mace will ultimately vote against the package. It’s also unclear whether there are any other potential holdouts; Gonzales, despite vowing a “no” vote, said he will not whip for other nays, suggesting his vote will be more of a protest than an actual attempt to defeat the package. But one lesson from the first chaotic week of the Republican House majority is that McCarthy can’t take any vote for granted. As Gonzales pointed out Sunday, the speaker vote should be “the easiest vote we’ll take in Congress,” and the rules package should be “the next easiest.” That McCarthy had to just about sell his soul to get through the former and may be biting his nails over the latter bodes poorly for his ability to navigate the far choppier waters he’ll soon wade into. This guy couldn’t even get his party unified around his speakership without agreeing to wear what Gaetz called a political “straitjacket”—how is he going to broker a deal to keep the government open? 

McCarthy, as something of a political arsonist himself, was already likely to make such spending negotiations later this year hell for Joe Biden and the Democrats. But thanks to his concessions to the even more extreme pyromaniacs in his party, who have proven capable of holding him hostage, he is sure to take an even harder line—to push for even more dramatic cuts to domestic and possibly even military spending—that could risk pushing the United States off a fiscal cliff. “There is a line in the sand here,” Democratic Senator Chris Van Hollen told the Washington Post of the GOP’s economic brinkmanship. “We’re not going to give the extreme Republicans their wish list in exchange for them simply allowing the country to pay its bills on time.” 

McCarthy was relieved to cross the finish line last week in his speaker race. But now, an even more grueling obstacle course lies ahead, with bitter, intra-party fights awaiting him at every turn. “The House of Representatives is a rough and rowdy place,” Gonzales said Sunday, predicting “ugly” battles ahead to do even the basic work of governance. “This is only the beginning.”