How to know when it's the latter?

When your coach is being associated, even in an unserious way, with someone who allegedly bilked investors out of roughly $50 billion through arguably the most diabolical Ponzi scheme in recorded history.

When your savior quarterback, Brett Favre, is hinting at the horrors that might appear on an end-of-season MRI.

And when it seems like the season all-but-officially ended a week earlier, in a snowstorm in Seattle, where defensive end Shaun Ellis showed better aim with a massive snowball than Favre did with the slippery Football.

Welcome to Jets camp before the season finale against the Dolphins. Take precautions. There's a high level of toxicity in the atmosphere.

That can't help but help the Dolphins, whose mission and minds are much clearer. The Jets' mission? Win, and hope that either the Patriots or Ravens lose to lesser opponents. The Dolphins' mission? Win and in.

The Jets' minds? So much clutter.

It could be Favre's last game as an NFL quarterback, Eric Mangini's last game as the Jets' coach and the team's last chance to avoid induction (along with the 2007 and 2008 Mets) into New York's Hall of Shame.

The Dolphins' minds? What could trouble them? No one expected them to get this far, not fans, not media. House money for months. No off-field drama. Coach on a honeymoon.

The Jets' coach was on a honeymoon once. That was 2006. He went 10-6, and earned the "Mangenius" label. Now he's experiencing the fallout of a heralded, expensive squad free-falling from 8-3 to 9-6. The hope and anticipation that Jets followers invested in this reconstructed roster has given way to fear and frustration, and a growing sentiment that the Jets' maneuvers amounted to just another Ponzi scheme.

Speaking of which . . .

A reporter informed Mangini that, on talk radio, "Bernard Madoff doesn't get the same kind of vitriol."

The Jets coach softly replied: "A little over-the-top in terms of comparison. Maybe the Grinch or something."

That would be more appropriate, since Jets fans seem to feel the softspoken coach has stolen their Christmas. Radio callers are chucking their endless supply of coal: mocking his passive sideline demeanor, bemoaning the absence of adjustments.

And in his 20-minute news conference, Mangini was put on the spot so many times, he should change his name to Johnny.

Would this game justify discarding Chad Pennington for Favre? "We're happy with that decision. This game won't justify or not justify that decision. . . . Brett was one piece in the puzzle."

Did he want Favre to return in 2009? "Yeah, yeah."

What if Favre decides this is it? "I have no idea. I mean, I have no idea."

Has owner Woody Johnson promised Mangini that he would return? "That's not something we talk about."

Mangini then gave way to Favre, who tried to focus on possibilities that a win Sunday could create, but whose presentation still came off like a postmortem.

"I'm disappointed," he said of the Jets' current position.

He said he was "thankful" that the team had allowed him to take this "gamble" this year, and said, unconvincingly, that he felt he had made the right decision because it had been "a lot of fun."

"Do I see myself playing here next year?" the 39-year-old said. "I didn't see myself playing here this time last year."

He said that his arm feels "OK," but admitted he hasn't made every throw he believes he can make. While he attributed "some of that to age," he intimated that a test could reveal otherwise. "I mean, just knowing my body, there may be something," Favre said, referring to his shoulder.

How could there not be? The unbearable weight of euphoria-or-disaster New York rests on that shoulder, as well as the shoulders of his beleaguered coach and teammates.