Don’t call it a failure. The Miami Heat actually accomplished a lot last season. In their first year together, LeBron James, Dwyane Wade and Chris Bosh succeeded just by reaching the NBA Finals.

But that won’t be enough this season. The next one, either. Or for several more if the all-star trio remains together.

The Heat’s warm-up period is over. Built to win NBA championships, the Heat must get one this season. If Miami falls short, team President Pat Riley should ask himself some tough questions about the group he assembled.

Bosh understands that urgency, and that’s why he’s concerned. Despite having the Eastern Conference’s second-best record, Miami has issues. The Southeast Division leader hasn’t been the defensive force it was last season.

Something is definitely missing, “and I’m not going to say it’s perfect,” Bosh said Friday before Miami’s 106-89 win over Washington. “It’s definitely not perfect. It’s not close to perfect.”

In many ways, Bosh is the conscience of the Heat. He’s a deep thinker as well as one of the league’s most athletic big men. He’s passionate about the team’s group dynamic.

Miami’s long playoff run last season occurred, in large part, because of the players’ accountability to one another, especially on defense. That was their foundation. Every defensive rotation, each assignment — the Heat was in sync.

This season, not so much.

“It’s not really good,” said Bosh, selected Thursday to his seventh all-star game. “We have to improve on it [accountability]. That’s one of the many things we have to get better at. We’re working on it.”

After television cameras captured Bosh sobbing after the Heat’s Game 6 loss to the Dallas Mavericks in last season’s Finals, he was the subject of ridicule in some media and among those fans eager to see the Heat fail. (Most fan backlash stems from James’s poorly handled exit from Cleveland after the 2009-10 season.)

I don’t have a problem with Bosh’s crying; I respect the honesty of his emotion. Obviously, Bosh is fully invested in his team’s attempt to attain greatness. The Wizards would be better, albeit only a little, if more of their top players cared about winning half as much as Bosh does.

In losing to the Mavericks, the Heat missed an opportunity, and Bosh understood the significance: Windows stay open only so long, and Miami missed its first chance.

“It’s always gonna be like, ‘Can we get there again?’ ” he said. “Knowing like, ‘I don’t know how we got there last year.’ It’s that difficult.”

For Miami, though, there was no shame in having a great playoff stretch and losing in the Finals against the Mavericks, whose talented core had been together longer. Regardless of individual talent, it usually takes more than one season for teams to come together when rosters are reworked as much as Miami’s was before the 2010-11 season. And in the Finals, Mavericks star Dirk Nowitzki gave one of the great postseason performances ever.

But moving forward, the Heat has to finish. Getting there isn’t good enough, and they know this.

“Getting that far . . . that was what was so difficult for me,” Bosh said. “We got that far, and it was the hardest thing I had ever done. There was no way you could have told me we weren’t going to win.

“I felt we deserved to win. . . . We have to do ourselves the service of making sure we prepare and play and hold each other accountable like champions.”

The Boston Celtics have demonstrated how fleeting success can be. They won the 2007-08 NBA title in the first season that all-stars Paul Pierce, Kevin Garnett and Ray Allen played together, and they envisioned winning many more championships.

Garnett’s injury during the 2008-09 season derailed Boston’s efforts to repeat. Then in the 2009-10 Finals, the Celtics held a three-games-to-two lead against the Los Angeles Lakers, but center Kendrick Perkins suffered a serious injury in Game 6. The Lakers won Game 7 on their home court. Now, the Celtics’ best days appear behind them.

Miami’s Big Three realizes “anything can happen like the Celtics,” Bosh said. “The Lakers had a little bit of a better record than they did, so they go there for Game 7.

“Home teams win most of the Game 7s. What if that Game 7 was in Boston? There are things that are gonna be outta your control sometimes.”

If Miami doesn’t win the championship this season, Riley should make some changes. Age wouldn’t be the problem. Wade turned 30 in January. James is 28, and Bosh turns 28 in March.

Group chemistry, toughness, determination — all could become concerns for Riley unless Miami proves it has it all. Doing so is simple: The Heat must win the last game of the NBA season.

For Jason Reid’s previous columns, go to