WASHINGTON — Nets Coach Steve Nash gave a pained smile in the barren hallway leading to the court at Capital One Arena. The Nets were in the middle of an implosion, having lost nine straight games, soon to be 10. He was asked about his unequivocal statement just days before that James Harden, the Nets’ All-Star guard, wouldn’t be traded.

“I still feel the same way,” Nash said. “Nothing’s changed.”

When pressed, Nash said, “He’s not told me he doesn’t want to stay, so I’m working off our conversations, which is he wants to be here and we want him here.”

It seemed like wishful thinking Thursday morning, the day of the trade deadline. Within hours, Harden was gone, breaking up one of the most highly touted so-called superteams in N.B.A. history. The Nets traded Harden, the former Most Valuable Player Award winner, to the Philadelphia 76ers for a package centered on Ben Simmons, a three-time All-Star who had not played all season for personal reasons.

Call it an extraordinary ending, but not a surprise. Harden has played with Chris Paul, Dwight Howard and Russell Westbrook — all likely future Hall of Famers he encountered in their relative primes. None of those pairings worked out. Then just over a year ago, he forced his way off the Houston Rockets to team up with Kyrie Irving and Kevin Durant in Brooklyn. He had shown up to Houston’s training camp late and out of shape, then showed such little interest in games that he was told to stay home. The message to the Rockets from Harden was clear: Trade me or I’ll make myself a spectacle.

The Nets knew who they were getting in Harden when they gave up so much to get him. They did it anyway. Live by player empowerment. Die by player empowerment.

“I’ve been in a situation too where I’ve asked for a trade and I understand it,” Irving said to reporters, referring to his demand to leave the Cleveland Cavaliers in 2017 with two years left on his contract. “So I’m not here to judge him. I’m not here to talk bad on James.”

Late Thursday, the Nets’ Twitter account posted an image of Harden with the caption, “Thank you for everything.”

“Make no bones about it: We went all in on getting James Harden and inviting him into the group,” Nets General Manager Sean Marks said at a news conference Friday. “These decisions to move on from a player like that of that caliber are never easy ones.”

The Superteam

When Harden came to the Nets, he had established himself as one of the best scorers ever, a man who could single-handedly power an offense with layups, step-backs and a torrent of free throws.

He had become known for wearing down defenders with his penchant for hooking their arms so quickly that it seemed as if he were being held — drawing fouls and annoying opposing coaches and players to no end. His tactics were becoming so prevalent across the league that the N.B.A. shifted its officiating emphasis this season to stop them. The change slowed him down for a few weeks, but then he adapted and looked, again, as if he might become the third superstar of a championship team.

But it’s worth remembering that the Nets didn’t need him.

If any player can match Harden’s offensive firepower, it’s Durant — a virtually unguardable forward too quick for defenders his size and too big for guards at his speed. His lanky frame and extended reach often make opponents look feeble as they put their hands up to try to block his shot. Durant is easily one of the three best players in the N.B.A. every year.

Not to mention Irving, who is also an elite scorer who operates with the ball seemingly on an invisible string, and who can change directions at any second with either hand. Defenders have to guess which way Irving will drive — and most of the time, they guess wrong. If they guess right, Irving, with a herky-jerky hesitation dribble, can easily reverse. Either way, defenders are left in the dust.

With Irving, Durant and Jarrett Allen, the center whom the Nets traded away with Caris LeVert and draft picks to get Harden, the Nets still would have been the most talented team in the league last season. Allen was clearly on his way to becoming the double-double anchor he now is for Cleveland. And since trading for Harden, the Nets have piled on more big names including Blake Griffin (six All-Star games), LaMarcus Aldridge (seven), Paul Millsap (four) and Patty Mills, one of the best backup point guards.

The only modern precedent for a core group at the level of Harden, Irving and Durant was when Durant went to the Golden State Warriors, where he won two championships alongside Stephen Curry, Klay Thompson and Draymond Green. With Harden, it should’ve been déjà vu. It ended up being a repeat, just not the one the Nets wanted.

In 2013, with the franchise struggling to attract fans in its new home of Brooklyn, the Nets acquired Paul Pierce and Kevin Garnett from the Boston Celtics to team with Deron Williams and Joe Johnson. On paper, it was a brilliant move, giving the Nets a roster of All-Stars ready to compete for a championship, at the cost of lots of draft picks — one pick which became Jaylen Brown, a Celtics guard who was an All-Star last year — and cap space. (Sound familiar?) They won one playoff series before the team fell apart. (Again: Sound familiar?)

How It Fell Apart

It’s unclear why or when Harden became so disenchanted with the Nets that he wanted another change of scenery. Marks said that trade discussions began in earnest in the last couple of days. Just a week ago, Harden posted a picture on Twitter of himself on the court with Irving and Durant with the caption “Scary Hours!”

They were certainly fearsome on the court. But they played together in only 16 games over the past two seasons including the playoffs, going 13-3. In the playoffs, they looked dominant against an overwhelmed first-round Celtics team and against the Milwaukee Bucks in the Eastern Conference semifinals, at least initially. It was a tantalizing tease of what could have been.

Irving and Durant have missed dozens of games with injuries, and Irving has played in just 13 games this season because of his refusal to be vaccinated against Covid-19. That has kept him out of home games in Brooklyn because of a city mandate, and the team barred him from road games and practices until mid-December. Last month, Harden told reporters that he would vaccinate Irving himself. It was said in jest, but perhaps a seed of resentment was in there, too.

Unlike Durant, Harden declined to sign a contract extension before the season, saying he wanted to be “patient.” He can opt out and become a free agent this summer. But he added, “I’m in the right mind-set and knowing long-term that ultimately I want to be in Brooklyn for the rest of my career.”

In recent weeks, several media reports indicated that Harden was unhappy and preferred a trade to Philadelphia to team with Joel Embiid, an M.V.P. candidate and the league’s leading scorer. The Nets had dropped to the eighth seed from near the top of the Eastern Conference, raising the previously unthinkable possibility of missing the playoffs.

Harden dismissed the reports last month and told reporters: “Of course I’m frustrated because, you know, we’re not healthy. You know, it’s a lot of inconsistency for whatever reason — injuries, Covid, whatever you want to call it.”

His last game with the Nets was Feb. 2 on the road against the lowly Sacramento Kings. Harden had one of the worst games of his career, shooting only 2 for 11 from the field. He looked listless and disinterested on defense. He was playing like someone who wanted to be somewhere else.

“James probably couldn’t see what we were getting into, obviously, with my status being in and out,” Irving said. “I saw a few things that maybe that could have impacted things, but who knows

This may just be who Harden, 32, is now. He may not want to deal with much adversity to win a championship. He came to Brooklyn to play with Durant and Irving and instead spent much of this season carrying the offense by himself. If the Sixers’ road isn’t easy, he may ask out again.

What makes this ending different from the Pierce-Garnett era is that the Nets immediately recouped some of their losses. This time, they also sent Millsap to Philadelphia, but have acquired Simmons, a flawed but valuable point guard; Seth Curry, a sharpshooter; and two first-round draft picks. That may still be enough to win a championship this season.

“James was honest with us and we were honest with him and I think it’s a move that enables him to have a fresh start,” Marks said, adding that it “enables this team to have a fresh start without trying to push things to make things work.”