Paul Ryan, who announced his retirement from Congress on Wednesday, did more than any other Republican to promote the Tea Party. Photograph by Mark Peterson / Redux for The New Yorker

Paul Ryan has always been younger than his rivals. He is two decades younger than John Boehner, his predecessor as Speaker of the House; three decades younger than Nancy Pelosi, the leader of the opposition caucus; and a decade younger than Barack Obama, his ideological foil. Ryan’s politics and his persona, which is somehow both abstemious and dreamy, never actually won over large numbers of young people. But in his rise over the past ten years, in his efforts to order the angry chaos of the Tea Party movement into something like a regular political coalition, he always gave the impression of having the benefit of time. Washington would be his, it seemed, long after Obama and Boehner and Pelosi and the rest had left town.

No longer. On Wednesday morning, Ryan announced that he will not run for reëlection in Wisconsin’s First District, and that he will resign as Speaker of the House. Ryan is forty-eight years old now, still youthful in bearing but no longer a prodigy. At his press conference in the Capitol, all the familiar elements were in place: the chirpy, caffeinated demeanor of the widow’s peak, the assuredness. The reasons he gave for his retirement were personal. His children, he said, were all teen-agers now, and his own father had died when he was sixteen. He did not want to be a “weekend” dad. “You do not last forever” in power in Washington, Ryan said. “It’s fleeting.” He was speaking of his own career. He might also have been speaking about his movement.

The Tea Party has been a major force in American politics for nearly a decade now, stretching back to the victories that it brought Republicans in the midterm elections in 2010. Ryan did not create the movement, but he did more than any other sitting politician in Washington to welcome it into the Republican fold, to insist that it shared with the G.O.P. establishment an ideological core: that its fury was just atmosphere, and that at its essence was the same stringent set of beliefs—about small government and low taxes—that Ryan himself had grown powerful professing. When the acrimony between the upstarts and the old guard split the House caucus and deposed Boehner, Ryan was the one figure who could repair the breach—who could look at the Tea Party and see his own image—and so he became Speaker of the House. With the rise of Donald Trump, he tried to repeat this maneuver. The new President was bestowed a chief of staff (Reince Priebus) and a press secretary (Sean Spicer) selected from the ranks of Ryan’s Wisconsin allies. And Ryan began insisting to the public that this new regime was headed not toward serial, incandescent feuds but toward tax reform, Obamacare repeal, and entitlement reform—that the order was regular, that the Republican Party was not materially changed.

Ryan was wrong. The idea that Ryan so often advertised during the 2012 Presidential campaign (when he was the Vice-Presidential nominee)—that the free market is an anti-poverty program—has disappeared from his party, and been replaced by the instinct to punch down. The deficits he said that he was in Washington to limit have, under his watch, ballooned. In the capitols of Republican-controlled states, where the Party’s scorched-earth partisanship has found its most extreme expression, the project is faltering, with a wave of special-election reversals and, more recently, mass teacher strikes. The ease with which Trump claimed the Party (recent polls have put the President’s approval rating among Republicans at almost thirty points higher than Ryan’s) showed how badly Ryan had misjudged things; it now seems clear that the Tea Party was an expressive movement, not an ideological one. In November, we will learn whether the whole era of small-government Republican partisanship that coalesced in the Tea Party will fade with Ryan, too.

The country will be better off now that Ryan has less influence. The major accomplishment he claimed on Wednesday morning was the tax bill that he and his colleagues passed last year, a piece of legislation loaded with giveaways to corporations and the wealthy, and which will only escalate the country’s profound inequalities. Whether his party will be better without him is not as clear. In Washington, insiders believe the next Speaker will be either the transactional House majority leader, Kevin McCarthy, of California, or the more stringent conservative Whip, Steve Scalise, of Louisiana, who last year was shot in an assassination attempt at a congressional baseball practice. Ryan was adept at finding euphemisms for his party’s aims, even as many members of his caucus devoted themselves to making a cult of victimized white men. They now find themselves under pressure—facing protests and electoral challenges—from coalitions organized largely by high-achieving women.

At his press conference, Ryan hedged a bit about the nature of his departure. He promised that he would “keep fighting” for entitlement reform, though he did not specify in what capacity. He suggested that he had “more thoughts” on who should replace him but said that this was not the time to share them. He emphasized that his kids are all teen-agers, and that he wanted to be at home with them, but of course adolescence is a temporary condition. For now, the soon-to-be-ex-Speaker is headed back to Wisconsin, a good place to ride out a wave: just after Ryan announced his retirement, election analysts at the University of Virginia and The Weekly Standard suggested that his safe congressional seat was now a tossup. Ryan is not yet fifty; he might be imagining a Presidential run in two years’ time, or six. But politics is changing quickly right now. He may not have a recognizable party to return to.