About six hours after taking to the Senate floor to announce his retirement and deliver a thundering indictment of his party, his president, and his country’s political culture, Arizona Senator Jeff Flake called me from his cell phone. He sounded tired.

“It’s been quite a day,” he said, sighing, and chuckling, and then sighing again.

For Flake, the day had begun with an interview in the Arizona Republic, in which he shared the remarkable news that he would not seek reelection next year. “There may not be a place for a Republican like me in the current Republican climate or the current Republican Party,” he told the paper. Shortly after the story was published, Flake delivered a righteously indignant speech from the floor of the Senate in which he railed against President Trump’s “reckless, outrageous, and undignified behavior,” and the partisans who try to defend and justify it. “I have children and grandchildren to answer to, and so, Mr. President, I will not be complicit,” he said. From there, he’d been hustled from one interview to the next, with barely a chance to catch his breath. Now, with the day winding down, he seemed to be in a more reflective mood.

Flake told me he started thinking seriously about bowing out of his reelection bid a few weeks ago. He was facing a well-funded primary challenger and a wrathful revolt from the Republican base over his public criticism of President Trump. The polls looked bad; the fundraising was daunting. And the more he grappled with what it would take to win, the more he realized he didn’t have it in him.

As he weighed the decision with his wife, Cheryl, he made a point of soliciting advice from each of his five children. One of his sons was serving in a Mormon mission overseas, and unreachable by phone, so they corresponded via email. Another, his youngest, had spent the summer interning at the Capitol. He was just a year old when his dad was first elected to Congress. “In some sense, it’s about all they know,” Flake said of his kids. “They’ve followed politics enough to know what works and what doesn’t in a campaign.” When it came time to finalize his decision over the weekend, the family was unanimous: “To a person, everybody realized … that to win the primary I would have to run a campaign that I would not be comfortable with, and that I wouldn’t be proud of. And they didn’t want me to do that.”

By the time we spoke on Tuesday night, the initial round of praise for his Senate speech had already begun to give way to a chorus of critics, like the New York Times columnist Ross Douthat, who dismissed Flake’s “surrender” as embodying “the not-quite-admirable courage of men abandoning the fray.”

So, I put the question to Flake: Even if defeat was likely, why not champion your principles on the campaign trail and let the voters have a choice? He admitted the prospect was tempting. “The pugnacious, competitive part of me wants to go down swinging,” he said.

But ultimately, he determined that any good such a martyrdom might yield would be outweighed by the grim realities of waging a doomed-to-fail campaign. “There are still several things I’d like to accomplish in the Senate this year,” he said. “And to spend every waking minute outside of my duties here dialing for dollars, and to be subjected to the kind of vitriol that comes with politics right now—it just wasn’t worth it.”

The first time I met Flake, it was just a few weeks after Trump’s inauguration, and I had been assigned to profile him for The Atlantic. The junior senator from Arizona had gotten a bit of attention in 2016 for being one of the few Never-Trump Republicans in Congress who held out until the bitter end, and I was interested in seeing how he would navigate the brave new world he found himself in. Over the next several months, I followed him as he trundled through Trump’s America, clinging to his optimism and ideals with his teeth.

I stood in the back of a raucous town hall in Mesa, Arizona, where Flake patiently took questions for two-and-a-half hours from liberal constituents who cursed and booed his every answer. “People here have legitimate concerns and are afraid,” he told me backstage. And I sat in his Capitol Hill office with him and his wife—both of them visibly shaken, and sad—the day after a gunman opened fire on the park where he’d been practicing with his colleagues for the upcoming congressional baseball game. (“Us? Here? Why?” he recalled wondering when the shooting began.)

For the most part, the arguments Flake laid out in the early months of the Trump presidency—whether about the president’s character, or the general decay of American politics—were as unoriginal as they were unimpeachable. The gist of his message was captured memorably in his speech on Tuesday:

We must never regard as ‘normal’ the regular and casual undermining of our democratic norms and ideals. We must never meekly accept the daily sundering of our country—the personal attacks; the threats against principles, freedoms, and institutions; the flagrant disregard for truth or decency; the reckless provocations, most often for the pettiest and most personal reasons, reasons having nothing whatsoever to do with the fortunes of the people that we have all been elected to serve … They are not normal.

But what I found most compelling about Flake as I spent time with him was not his ideas, but the way he wrestled with the seeming hopelessness of his project. In the face of overwhelming evidence to the contrary, he was adamant that soon enough everything would snap back to normal, and America would experience a grand return to civility, decency, and productive bipartisan governance. After all, he would argue, that’s what the American people really want—and as more public servants joined him in this cause, the voters would lend their validation.

As we talked Tuesday night, Flake made this case valiantly. He said, “I think after the fever breaks, this’ll pass.” He said, “Resentment is not a governing philosophy, and we’re gonna have to govern.” He said, “We’ll have to go back to some semblance of the old normal.”

“When you look at our history,” he assured me, “we’ve been through some tough, tough things. And we’ve made it through. These institutions are durable and well constructed, and they are built to withstand the foibles of man.”

But I always thought I could detect doubt just beneath the surface of these faithful civic sermons of his—and this time was no different.

Maybe Flake is right, and what we’re seeing unfold in this ugly moment of American history is an aberration. Maybe what the country is waiting for is someone to “reawaken [its] conscience,” as Flake wrote in a Washington Post op-ed—someone decent and honest who can deliver a “shock to the system” and remind us all “who we are supposed to be.” Maybe that person will be a liberated lame-duck senator who spends his final year in office bravely speaking truth to presidential power. Maybe that senator, although temperamentally averse to bare-knuckled political brawling, will decide that’s what it will take it to prevail. And maybe, just maybe, he will get a chance to run for president himself in the not-too-distant future.

But what we know for sure, today, is that a senator who saw himself as fighting for the soul of his party has been chased off the battlefield, forced into retreat. In the profile I wrote in September, I asked: Is there no longer a place in politics for someone like Jeff Flake? This week, it seems, he gave us the answer.