No one person bears singular blame for the current state of American politics. It took many different choices, from many different people, to produce President Donald Trump. And it took even more choices, from an even greater range of people, to produce the present-day Republican Party, so caught in the grip of entrenched interests, hard-right ideology, and social revanchism that it was primed for the racist, authoritarian, and kleptocratic politics of a Trump. But some people bear more responsibility than others, and Paul Ryan bears more than most.

Ryan announced on Wednesday that he will not seek another term in the House, making him the highest ranking—and highest-profile—Republican to call it quits this cycle, a major setback for those trying to save the party’s majority from a wave of Democratic enthusiasm. His retirement is a vote of no confidence, and it could prompt other GOP lawmakers to follow his lead.

Despite his obvious misgivings, the speaker backed Trump when it mattered.

Ryan is leaving in the wake of his signature legislative accomplishment: a $1.5 trillion tax cut with long-term gains for large corporations and big benefits for the wealthiest Americans. It is, perhaps, his only accomplishment. Ryan, along with the rest of the Republican Party, failed to repeal the Affordable Care Act, and he’s done little to shrink the national debt despite years of dire warnings around the threat of heavy debt loads. In fact, he’s done just the opposite. His tax cuts will supercharge annual deficits, according to a new projection from the Congressional Budget Office. Red ink will dominate the U.S. budget ledger, and by 2028, the debt will approach 100 percent of gross domestic product. And instead of accelerating growth, the CBO projects a substantial slowdown in the years ahead.

Ryan’s fiscal hypocrisy is typical of Republicans, who exploded the debt with major tax cuts in 1981, 2001, and 2003. To the extent that he has innovated on the GOP approach, it’s in merging anti-tax policy with extreme cuts to the social safety net. If Ryan has a particular skill, it’s presenting this radical departure from the present order as nothing more than simple book-balancing reform.

This is Ryan’s legacy. Or it would have been, had he retired at any point before 2016. Now, his legacy resides squarely in his decision to enable Donald Trump and his rise to power within the Republican Party. Brutal, corrupt, and shamelessly demagogic, it was clear from the moment he announced his campaign that Trump was unsuited for the White House. There were times when Ryan felt compelled to acknowledge this. “He doesn’t speak for the Republican Party, and I think his comments were extremely disrespectful, and I don’t think that’s the way to have an immigration conversation,” said Ryan after Trump accused Mexico of sending “rapists” to the United States. When Trump tried to issue his Muslim ban, Ryan said, “What was proposed yesterday is not what this party stands for. And, more importantly, it’s not what this country stands for.” Ryan said he was “sickened” by the Access Hollywood tape and called Trump’s remarks on Judge Gonzalo Curiel “the textbook definition of a racist comment.”

And yet, despite his clear distaste for Trump, Ryan ultimately stood by him once the reality television star became the party’s nominee for president. He never withdrew his endorsement, never did anything that might jeopardize Trump’s ability to win the vast majority of Republican voters to his side. With Trump and a Republican Congress, Ryan could achieve his dream of radical cuts to the welfare state and an end to the New Deal order. Faced with evidence that Trump tried to improperly influence of the Department of Justice, Ryan shrugged, “He’s just new at this.” And when it was clear that Rep. Devin Nunes, chairman of the House Intelligence Committee, was running a countercampaign against the investigation into Russian election interference, Ryan all but stood with Nunes as he tried to discredit FBI officials.

Before Trump seized the reins of the Republican Party, Ryan was the closest thing to a bona fide party leader. He had been the party’s vice presidential nominee in 2012, and his strong backing from most factions within the GOP made him a consensus candidate for the speakership. A strong objection from Ryan during Trump’s campaign, a move to withdraw his endorsement, a true rejoinder to Trump’s authoritarian impulses—these may have made a difference in stopping Trump’s rise, or at least raised barriers to his success. But Ryan, a lifelong ideologue, was willing to risk the constitutional order for the sake of his agenda. Which is to say, tax cuts.

Ryan told reporters on Wednesday morning that the speakership “is a job that does not last forever… You realize you hold the office for just a small part of our history. So you better make the most of it. I like to think I’ve done my part, my little part in history, to set us on a better course.”

It will be up to historians to decide whether Paul Ryan played such a “little part” in Donald Trump’s rise and whether, together, they set the country on a “better course.” There’s no reason to think that verdict will be kind.