Confetti rained down around Bill Belichick and Tom Brady as the two hugged near midfield, Super Bowl champs together for the sixth time. It was Feb. 3, 2019. Belichick patted Brady’s shoulder pads twice. Robert Kraft, the longtime owner of the Patriots, embraced the quarterback. He told Brady he was the best ever.

They all partied together that night in Atlanta as the franchise celebrated an unmatched run of dominance. The Chainsmokers and Snoop Dogg performed.

With the Patriots’ Super Bowl LIII win over the Rams, Kraft, Belichick and Brady each cemented their status as the most successful at their respective position in NFL history. No owner, no coach, no quarterback could match the stretch of winning that the three architects of the Patriots dynasty had orchestrated.

But behind the scenes, the relationship between Brady and Belichick was fraying. The things that had made them such a good pairing for 20 years were now pulling them apart.

Brady left New England after the 2019 season to sign with the Tampa Bay Buccaneers. The following season, he led the Bucs to a Super Bowl title, the seventh of his storied career. Over the last four years, the Patriots, meanwhile, tried Cam Newton, Mac Jones, then Bailey Zappe at quarterback as their offense slowly decayed into one of the league’s worst.

After arguably the best 20-year run in league history, the Patriots haven’t won a playoff game since that Super Bowl in Atlanta five years ago. They’re 29-37 since Brady left and 4-12 this season, earning their first last-place finish in the AFC East since 2000, Belichick’s first year on the job. Now, they’re just a week away from a potential major sea change. Rumors abound — as they have for much of the fall — that Belichick and the Patriots may part ways at the end of the season.

Answers about the franchise’s future are expected to come following a sit-down between Kraft and Belichick shortly after the Week 18 game against the New York Jets that matters only in how it will affect New England’s 2024 draft position.

The Athletic spoke with multiple team and league sources familiar with the thinking inside the building to examine how the most successful relationships in NFL history soured, putting the Patriots in a downward spiral and on the doorstep of franchise-altering questions.

For so long, Belichick was the perfect coach for Brady. The three-time NFL coach of the year took a shovel to the chip on Brady’s shoulder. The quarterback was at his best when he believed he’d been slighted, when he could make an enemy out of the smallest knock on him. And Belichick picked at that wound. He pointed out Brady’s flaws in team meetings more than any other player. For a long time, Brady thrived on that.

And for so long, Brady was the perfect quarterback for Belichick. He believed in complementary football, willing to put his stats aside for the benefit of the team. He took discounted contracts to help Belichick build out the roster at other positions, and he didn’t complain if those additional resources weren’t used on the offense.

But by the end of 2019, celebrating another Super Bowl felt like a distant memory. The relationship between Brady and Belichick was fractured. After six Super Bowls and three MVPs, Brady was 42 years old and didn’t want to be antagonized at work anymore. He wanted the kind of contract that meant he wouldn’t go anywhere until he was 45, ensuring he retired as a Patriot. Belichick wouldn’t commit to that kind of deal.

Brady complained to Kraft throughout 2019. Belichick did the same. That wasn’t necessarily new. Kraft heard independently from the two sides for over a year, often aptly walking the tightrope of letting each side vent without making rash decisions, keeping together the most successful relationship in NFL history even when it felt like they were near a boiling point. Many within the organization credit Kraft for his work as a middleman, keeping Brady and Belichick together long enough to win that sixth Super Bowl.

Kraft’s final ploy to keep together the best coach-quarterback duo in league history was to ensure Brady would have the chance to be a free agent at the end of 2019. He hoped that would incentivize Belichick to make changes. Treat Brady differently. Make him a bigger part of the operation. Focus on the offense more.

But Belichick refused to change. He told Kraft that Brady’s play was declining. As painful as it was to say goodbye to Brady, which he did during an in-person chat at Kraft’s home, the owner understood why Brady wanted to leave, and Kraft trusted his longtime coach that the separation would eventually help the Patriots.

Since Brady’s departure, though, Kraft has grown frustrated as his team, once a model of success, has cratered into one of the NFL’s worst.

Belichick, meanwhile, has expressed irritation that all the success he’s helped provide hasn’t garnered more deference during this decline. When asked before the 2023 season why fans should still be optimistic about the Patriots, Belichick quipped, “I don’t know — the last 25 years?”

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In the days before this season began, Belichick, 71, spoke with a reverence for Brady that he hadn’t to that point. Brady was returning to Gillette Stadium for the first time since his retirement for a ceremony that included a halftime speech.

As the event neared, Belichick called Brady the best offensive player ever. He said that one night wasn’t nearly enough to celebrate the former quarterback. Asked for a favorite memory, Belichick said, “There are six of them that come to mind.”

For longtime members of the organization, it was jarring to hear Belichick talk like that after years of hard coaching and limited praise for Brady. Some were left to ponder difficult questions: If Belichick had spoken like that in the final years with Brady, might the quarterback have stayed in New England? Would they have a seventh Super Bowl ring together? An eighth?

Tom Brady and Belichick in 2019. (Adam Glanzman / Getty Images)

But Belichick hasn’t changed. And he wasn’t going to for one player, even Brady. He may have a dry sense of humor away from the cameras, but for the most part, what you see is what you get. His demeanor inside the team’s headquarters isn’t that different from the gruff, stoic attitude regularly on display at his news conferences.

Patriots Hall of Famer Kevin Faulk once said he walked past Belichick in the hallways for years, greeting him every day without so much as a “Hello” in return. Players seldom hear flattering remarks from their coach. “He definitely serves a lot of humble pie,” safety Jabrill Peppers said. “He don’t praise nobody,” linebacker Mack Wilson agreed.

That can make it difficult to relate to young players who join the Patriots, a different generation that wants to understand why the team is doing certain things rather than just being ordered around, one that likes to be complimented and recognized for its hard work.

In many ways, the Patriots do things differently than the rest of the league, mostly because of how Belichick runs the show. They’ve been reluctant to embrace sports science and analytics. Belichick once said he uses analytics “less than zero” to make in-game decisions. The Patriots are one of only four NFL teams that don’t employ a multiperson analytics and research department. It’s fair to reason they haven’t modernized the way most other teams have because Belichick hasn’t seen the need to with the six Lombardi Trophies as evidence for continuing to do things his way.

While most other teams have seen their coaching staffs balloon with extra assistants in recent years, Belichick has opted to keep his inner circle tight. So the Patriots began this season with 18 assistant coaches, including only eight on offense. (The 49ers, by comparison, have 27 on staff, including 14 on offense.) That was especially troubling in 2023 when two offensive assistants left midseason. Offensive line coach Adrian Klemm left the team in November for a “health-related” issue, Belichick said, and wide receivers coach Ross Douglas left in early December to take the same job with Syracuse.

Given the small size, Belichick demands more from his staff. The group went to Las Vegas last January to coach one of the teams at the Shrine Bowl, a pre-draft showcase game for college prospects. Arthur Smith’s Atlanta Falcons staff was in charge of the other team. Smith worked his assistants hard during the day but allowed them time off to have fun and get to know each other at night. Belichick took a different approach. His staff spent 12 hours a day preparing for the game. Then, once that work was done, they spent their nights studying for the coming NFL season — seven months away.

It also hasn’t helped that some of Belichick’s top lieutenants have departed for other jobs, further isolating an already reclusive coach. Josh McDaniels, who worked with Belichick for 18 years, left to become the Raiders’ head coach. Brian Flores, who worked with Belichick for 11 years, left to take the head coaching job with the Dolphins. Dante Scarnecchia and Ivan Fears, the position coaches Belichick trusted most, retired after a combined 40 years under Belichick. Right-hand man Ernie Adams retired after 20 seasons with Belichick.

The same happened in the player personnel department, which Belichick also leads. Nick Caserio became the Texans’ general manager after 20 years with Belichick. Dave Ziegler left to become the Raiders’ general manager after nine years under Belichick. Monti Ossenfort left for the Texans and then got the Cardinals’ general manager gig after working with Belichick for 14 years.

Belichick is slow to trust and values familiarity over the unknown. He doesn’t want to teach a whole new coaching staff how to do its job. So he replaced those assistants with familiar faces, even if they lacked the proper qualifications. That led to Matt Patricia, a defensive specialist, and Joe Judge, a former special teams coordinator, jointly running the offense in 2022, a crucial year for second-year quarterback Mac Jones. (New England went 8-9 and Jones struggled mightily.)

With those departures, Belichick lost many of his sounding boards. His decision-making became even more siloed. In a league that increasingly values collaboration and a confluence of ideas, the Patriots are an anomaly. Belichick decides everything. Scouts can spend years getting to know everything about a prospect, but if Belichick doesn’t agree with the assessment, they’re often overruled.

His draft classes have long struggled. Astoundingly, Belichick hasn’t re-signed a player he drafted in the first three rounds since 2013 (Duron Harmon). In 2022, he chose a left guard in the first round who was seen by most experts as a third-round pick at best, then in the second round chose a wide receiver (Tyquan Thornton) who can already be labeled a bust. His 2021 first-round pick (Jones) has been benched, and his first-round pick in 2019 (N’Keal Harry) was such a bust that he was off the team three years later.

That caused Kraft to up the pressure on Belichick in the spring of 2021, bemoaning the results of his recent draft classes and insisting on improvement. “If you want to have a good, consistent, winning football team, you can’t do it in free agency,” Kraft said. “You have to do it through the draft.”

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But Belichick, who came up studying defenses, has been unable to fix the team’s offense. The Patriots rank last in scoring this season.

Instead, Belichick has sought to win by zigging when everyone else zags. He planned to win this season with defense and special teams, investing more resources into special teams than any other coach in the league (the Patriots have seven players on their 53-man roster solely dedicated to the unit). Yet, they rank last in the NFL in field goal percentage, 31st in yards per punt return and 23rd in net yards per punt.

The 82-year-old Kraft has taken it well that he’s been passed up for the Pro Football Hall of Fame the last two years, even if his absence surprises many around the league.

His resume warrants a spot in Canton. He has helped turn the Patriots into a model organization. He built Gillette Stadium, paid for the recent renovations and oversaw the creation of Patriot Place around the stadium, a multi-use commercial complex that started a trend around the NFL. He chairs the league’s core media committee, which was responsible in 2021 for securing a new media rights deal reportedly worth more than $100 billion. He has become a trusted confidant of commissioner Roger Goodell. He was credited with helping broker the deal in 2011 that helped end the league’s first lockout in 24 years. And then there are those six Lombardi Trophies that reside in Foxboro.

Still, the votes haven’t yet come, though Kraft has been a finalist for the last two years. His next chance to be inducted is with the Class of 2025.

So Kraft remains cognizant of his image and careful in his decision-making. It’s unlikely he’ll decide Belichick’s fate with his Hall of Fame candidacy top of mind; there are bigger issues at play. But whatever decision Kraft makes will be part of that legacy, adding extra weight to an already difficult and important choice. After Kraft watched Brady win a Super Bowl elsewhere, how painful would it be if Belichick did the same?

“Before I make a final decision,” Kraft once wrote, “I measure nine times and I cut once.”

That’s why it’s no surprise that Kraft has been calculated regarding this decision about Belichick. It’s not going to come lightly. In 30 years of ownership, he has only worked with three head coaches and is proud all three have found lasting success (Bill Parcells, Pete Carroll and Belichick).

Of course, there’s been a lot to like in the 24 years Kraft and Belichick have worked together. But that hasn’t continued in recent years, which is why Kraft challenged Belichick in 2021. For a relationship that had been so successful for so long, it was one of the first public critiques of Belichick’s plan and results.

Belichick, for his part, seemed to begin playing his own games through the media from that point on. He praised several other ownership groups and the facilities of several other teams while conspicuously refraining from praising the Krafts and the renovations they’ve privately funded at Gillette Stadium. Meanwhile, he’s said little publicly about Robert or Jonathan Kraft. His only comments about the $250 million renovation the Krafts completed this year were about how the bigger video board might affect wind patterns for the kickers.

In August, just before Kraft found out he hadn’t been selected for the Hall of Fame, Belichick was given a chance to publicly back the candidacy of the guy who signs his paychecks. It was a softball of a question, but Belichick was brief in his answer.

“Keeping our fingers crossed that we get the vote this year,” he said.

To Belichick backers, it was a simple sign of support for the owner. He was hoping Kraft would get the votes. What more could you want?

But others saw it as a less-than-full-throated endorsement. Belichick is often brief when discussing his current team, but it’s not uncommon for him to talk for several minutes about long snappers, left-footed punters or Curly Lambeau’s playbook. Yet when it came to his boss’s place in NFL history, his answer lasted 11 words.

(Vincent Carchietta / USA Today)

On Dec. 17, Kraft sat quietly in his owner’s suite below Section 310 as the Patriots lost their penultimate home game to the Kansas City Chiefs.

It was a cold Sunday afternoon. It felt like there were more Chiefs fans in attendance than those of any opposing team in years. The scene was a far cry from what the NFL envisioned at the beginning of the season when this game had been tabbed for “Monday Night Football.”

But even all the favor Kraft has built with broadcast partners and the stardom of the Chiefs — like reigning MVP Patrick Mahomes, all-world tight Travis Kelce and even pop superstar girlfriend Taylor Swift — wasn’t enough for ESPN and the NFL to want the slumping Patriots as part of their prime-time slate. They moved the game from Monday night to Sunday afternoon, another gut punch for Kraft and his team in a season full of them.

Now change feels inevitable. Some see it as a sign of respect that Kraft didn’t fire Belichick outright following one of several rock-bottom moments this season. But that said, it’s hard to imagine simply running things back with minimal changes.

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Perhaps Kraft might be enticed to keep Belichick as the coach if he’d relinquish power elsewhere (like control of player personnel or the draft), but it seems unlikely that Belichick, mastermind of six Super Bowls, is going to willingly give up the authority he’s amassed.

What seems most likely is a mutual parting of the ways, a chance for the Krafts to celebrate and thank Belichick for the years of success while bringing in a new voice to lead the organization. The Patriots could also try to seek draft compensation from another team by trading Belichick, but the coach would have to be on board with that plan. Or maybe the two sides can somehow put this season behind them, surprise onlookers around the league and keep their relationship going for another year.

Their collaboration has been far more successful than either imagined when it began nearly 25 years ago with Belichick scribbling on a napkin that he was resigning from the Jets after one day as their head coach to join Kraft and the Patriots.

Kraft gave Belichick what he always wanted, autonomy in football operations, and let him flex an unparalleled football acumen built as a schoolboy studying football with his dad at the Naval Academy.

And Belichick gave Kraft what he had dreamed of. Before owning the franchise, Kraft was a diehard season ticket holder watching bad Patriots teams on cold days in a decrepit stadium. Belichick gave Kraft a football team that won more than any other. Kraft gained clout and status amongst an ego-filled group of billionaire owners, none of whom could match Kraft’s success.

But five years after that last Super Bowl, the Patriots are a shell of their once-dominant selves. By the two-minute warning of that Week 15 game against the Chiefs, another double-digit loss was already decided.

Fans headed out for an early exit. Kraft did, too. He got up from his usual seat next to Jonathan and looked around. Visiting fans were filling the lower bowl to cheer on their team. Kraft looked at Jonathan and the two got up to leave.

There was no point in watching this any longer.

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(Illustration by Eamonn Dalton / The Athletic; photos: Jessica Rinaldi / The Boston Globe via Getty Images, Jim Davis / The Boston Globe via Getty Images, Matthew J. Lee / The Boston Globe via Getty Images, Jamie Squire / Getty Images, Matthew West / MediaNews Group / Boston Herald via Getty Images)

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