GRAND RAPIDS, Mich. — There comes a time in a young man’s life when things begin to change. Muscles develop. Relationships get complicated. He starts seeing himself differently, trying to figure out where he fits in. It can be confusing, thrilling, shameful.

For Justin Amash, 39, that time is now.

In recent weeks, the Trump-wary congressman split with the Republican Party to identify as an independent; he’s been criticized by his closest colleagues and developed a pumped-up physique that has people asking whether his new workout routine is about getting camera ready for a third-party presidential run.

“It’s obviously something that is realistic,” Amash said, over dinner in a crowded bar in late August. “If someone were to do something like that, there’s obviously a good chance it would be me. . . . It’s something I could decide to do.”

Amash has entered this kind of popularity contest before, but this time it’s different. He was once part of a tightknit group of rabble-rousers, but Donald Trump’s presidency changed the rules for what it meant to belong. Now, whether running for reelection (his current plan) or for the White House (possibly as a Libertarian), the Michigan congressman needs to figure out who his friends are.

And it’s not like he’s going to win over voters as the guy they’d like to have a beer with.

“I’d be the guy at the party where everyone was drinking, and I wouldn’t,” he said, sipping a Coke and eating a Cobb salad. “I’ve never smoked pot. Never smoked a cigarette. I have had alcohol, but not a great deal, pretty rarely.”

It’d been a long day of politicking for Amash, who late last month held his first series of public events at home since his leaving the party. He toured coffee shops and breweries; argued with Democrats about the Second Amendment; tried to convince Trump fans that his criticisms were consistent with his long-held beliefs; and fielded concerns from supporters that his going rogue could make the district vulnerable to less scrupulous politicians (or, as one constituent put it, to “tribal buttkissers”). Such is the lot of a Never Trump conservative — ultimately they disappoint all people at some point.

Rep. Justin Amash (I-Mich.) left the Republican Party after long criticizing President Trump. And on July 7, he would not rule out a 2020 presidential bid. (The Washington Post)

With his jet-black hair gelled down, chiseled chin, and eyebrows trimmed into perfect furry triangles, Amash looks a bit like “Star Trek’s” Spock and prizes himself for having a Vulcan-like ability to put logic over emotion. (“You don’t need to be scared of this stuff,” he’d told a woman earlier that day after she’d talked about losing friends in the 2007 Virginia Tech mass shooting. “Statistically speaking, it is not common.”)

He can, in other words, come across as cold.

“Basically all elected officials, they get satisfaction from being loved by their peers,” Amash said, leaning forward on the table, his voice as flat as a therapist’s. “All my life I’ve loved the feeling of being principled.”

As a member of Congress, he voted against so many bills that he earned the “Dr. No” sobriquet that once belonged to Texas gadfly Ron Paul. He helped found the Freedom Caucus, a bloc of conservatives that former House speaker John A. Boehner referred to as “anarchists.”

And yet at this point in his life, Amash seems to have hit political puberty and grown into Mr. Peace, Love and Understanding. He’s talking a lot these days about “trust,” “decency” and “civility,” reminding constituents that those with differing opinions are not evil but rather have “different life experiences.”

He’s positioning himself as someone who can splash cool water on a system that burns with partisan rancor. And he might be. But he also might be trying to put out fires he helped set in the first place.

“I used to be more inclined to think Democrats are bad; Barack Obama is uniquely bad or whatever,” Amash said. “Over time, I’ve come to see I was too harsh in many ways. I feel like I’m a better person today.”

Amash rode the 2010 tea party wave to Congress — America's high school for adults — and fell in with a group of conservatives who saw him, initially, as kind of a weirdo. His parents are Arab immigrants (his father from Palestinian territories and his mother from Syria), he quoted F.A. Hayek, and at votes — where members would spend time backslapping and gossiping — Amash was a quiet presence, sitting alone with his iPad and crafting long Facebook posts explaining his votes to constituents.

“He was a lovable nerd,” said Joe Walsh, a former congressional classmate of Amash who has recently launched a primary run against Trump.

Amash arrived at the Capitol from the Michigan legislature, where he served two years and earned himself the sexy reputation of reading all of the bills, thoroughly. “He had one of the first successful amendments on the floor from a Republican in a Democratic supermajority,” recalled former legislator Bob Genetski, who sat next to Amash in the statehouse. “He noticed a missing comma in one of the bills, and they gave him an amendment to change it.”

It’s the kind of accomplishment that sends eyes rolling skyward, like getting a spelling mistake corrected on an Arby’s marquee — another thing Amash once did, according to Jordan Bush, a former staffer and friend since kindergarten (the transgression: “Peacan Pie”).

“He just can’t let something be wrong that could be right,” Bush said.

He was always like that, Bush said: A kid without a curfew because he never gave his parents reason to worry, who did his homework unprompted and who married his high school sweetheart.

In Washington, Amash represents Michigan’s 3rd District — home to Grand Rapids, rolling farmland, furniture manufacturers and Gerald Ford — which had been known as a breeding ground for moderate Republicans. Amash didn’t exactly fit the mold.

As a constitutional conservative, he was, at any given time one of the most conservative members of the party (on, say, fiscal issues) and the most liberal (with regard to civil liberties).

He found plenty of like-minded members in Congress who also worried about the consolidation of power at the top. He threw himself in with fellow backbenchers, and in 2015 the clique made it official by forming an invitation-only group of about 40 called he Freedom Caucus, a name they agreed was both meaningless and unobjectionable, and because it was better than another idea floated — The Reasonable Nutjob Caucus.

Amash, one of the group’s more cerebral members, wrote the mission statement.

In theory, the idea of the caucus was to encourage more accountability from leadership, but in practice, it became a bloc just big enough to challenge any vote and often succeeded in pulling policy discussions further to the right than was tenable. If the House were high school, they were the classroom saboteurs tormenting their teachers and carving “school sucks” into their desks. “As you can tell, I’m not a fan of government,” Amash said.

Rather than deal with the likes of them for another term, Boehner resigned as speaker in 2015. Late last year, the Freedom Caucus was a driving force that led to the longest government shutdown in history.

“It is definitely ironic,” Boehner’s former spokesman, Michael Steel, said about Amash, “that someone who spent their legislative career being the gum in the works, keeping things from happening in a civil and bipartisan manner, is now preaching unity.”

Amash and the caucus were heroes to the grass roots, torchbearers of the tea party movement, fighters of the powers that be. And his brand of conservatism seemed to be on the rise.

“Has the Libertarian moment finally arrived?” asked the New York Times Magazine in 2014. Time Magazine, meanwhile, declared future presidential candidate Rand Paul, son of Ron, as the “most interesting man in politics.”

Around that time Amash started nursing presidential ambitions, said Matt Welch, an editor at Reason Magazine who has followed Amash’s career closely. “He mentioned to me,” said Welch, “that he told Rand, near the end of his [presidential] campaign, ‘I’m 35 now, so you better watch your step.’”

His friends thought the idea was crazy.

But not crazier than what actually happened.

What actually happened was the rise of Donald Trump, who didn't so much make friends with the Freedom Caucus as steal its social capital while abandoning huge parts of its ideological raison d'etre. Amash and his classmates realized that they would have to adopt Trump as their leader or risk a schoolyard scuffle.

Caucus member Rep. Mark Sanford (R-S.C.), chose the second option, and the outcome made Amash reconsider what it meant to be part of the group.

“Is Mark Sanford here?” Trump asked the crowd of Republican congressmen gathered in an auditorium in the Capitol late last June for a meeting with the president. “I just want to congratulate him,” Trump said sarcastically, “on running a great race.”

Sanford, who wasn’t there, had been an unapologetic critic of Trump, and had just lost his primary to a GOP candidate allied with the president. Over dinner with his friends from the Freedom Caucus that night, Sanford found out what Trump had said and learned who had his back.

“Justin said, ‘We have to defend Mark, because if he goes after him, he could go after any of us,’ ” Sanford recalled in an interview. “Everyone else there, well, they just kinda stared at their toenails.”

Amash left that dinner frustrated. The Freedom Caucus used to stand for something, and now it was just another group of Trump cheerleaders. When Barack Obama was president, its members were some of the loudest critics of spending and executive overreach.

Today, one of its founding members, Mick Mulvaney, is Trump’s acting chief of staff and budget director, helping oversee historic spending and ballooning deficits. Reps. Jim Jordan (R-Ohio) and Mark Meadows (R-N.C.) have become some of the president’s loudest defenders, even as he stretches the limits of executive authority, declaring a state of emergency on the southern border in order to divert funds to pay for his wall.

It’s all basically “performance art,” said Amash, who was not shocked by their turn toward Trump as a way to “survive until the next season.” You’d be surprised about what these same people say about the president when the camera is not on, he said.

Soon after the dust-up over Sanford, Amash decided he’d had enough of the show. The next day, he pressed send on a tweet calling Trump’s visit a “dazzling display of pettiness and insecurity,” and decided to take a little time away from the Freedom Caucus.

“He ghosted them,” said Corie Whalen, his former communications director.

"Last month, I became an independent on Independence Day" Amash said on the third stop of his reintroduction tour.

He was speaking to a crowd in a brewery outside Grand Rapids, rocking back and forth on his heels, his voice rising in volume and pitch, like a student giving a book report. Most of the crowd already knew the basics: that after calling for Trump’s impeachment, he’d announced his departure from the Republican Party in the pages of The Washington Post, urging readers to join him in “rejecting the partisan loyalties and rhetoric that divide and dehumanize us.”

Anyone paying attention also knew that’s not exactly what happened.

“Great news for the Republican Party as one of the dumbest & most disloyal men in Congress is ‘quitting’ the Party,” Trump tweeted. “. . . A total loser!”

The Freedom Caucus refused to come to his defense (there was no Justin Amash to stand up for Justin Amash), and many of them either declined to comment or spoke on background wondering out loud what’s gotten into him.

“I think he has a deep, visceral dislike for the president, and he’s let it define him,” said Rep. Thomas Massie (R-Ky.), not a Freedom Caucus member but one of Amash’s closest colleagues in the House — both ideologically and personally.

It’s true that Amash, when prompted, will not hide his distaste. He says Trump is being “racist” when he urges immigrants and people of color to “go back and help fix the totally broken and crime infested places from which they came.” He’ll call Trump a liar, “narcissistic,” and “amoral.”

But as Amash made his way through his district on that late-summer day, when he talked about Trump at all, it was to call him a symptom of a bigger problem.

People in the crowd who had seen him over the years had heard him complain for years about the corruption that comes from a top-down, two-party system, the lack of accountability in Congress, the worries about government overreach.

The truth is, for all the ways he’s changed, Amash remains the same. It’s the rest of the world that seems to be upended.

“I don’t hate the president,” Amash said that night, as he finished his Cobb salad. “He’s doing bad things to the country, and I wish he would stop. But I don’t hate politicians I disagree with.”

Amash will head into next year without an official friend group, which might make sticking around that much harder. But the thing about growing up is, at some point, eventually, you have to leave high school.