What happens when you absolutely, positively, no doubt about it, have to do something, and you don't do it? You simply don't do it. What then? (Pause.) Well, there you jolly well are, aren't you?

And now what for the Washington Capitals? No first place. No guaranteed home-ice advantage all the way through the playoffs until the final itself. No banner. No Rangers.

It's rerun time again, movie fans. "Mr. Smith Goes to Washington." Or, as we say on the Beltway: Here come the Islanders. Again.

About an hour before last night's game, admittedly the most important regular-season game in the 12-year life of the Capitals, their young but ashen-haired general manager, David Poile, paced gingerly in the hallway outside his team's locker room.

"Nervous?" someone just making small talk asked Poile.

"Sure, I'm nervous," Poile allowed. Then, smiling, he added, "Shouldn't I be?"

Sure, with good reason. The Capitals, needing this particular victory to win their first division championship ever, were in the lion's very den, having to play the only team in their division with a better record: Philadelphia in Philadelphia where Philadelphia had lost only six times in 39 games this season. The Capitals hadn't beaten Philadelphia here since the playoffs two years ago. In their three losses here this season, the Capitals had scored one goal, given up nine. Nervous? Who wouldn't be?

But, Poile acknowledged, if not now, when? "We're ready," he said. This game, the 80th and last of the creeping NHL season -- in effect the lone critical one -- had been such a long time coming. "We've been getting ready all year for this. We've been getting ready for this for the last three years," Poile said dreamily. He clapped his hands, in what was more of a return to reality than a gesture of excitement, and considered the scripts. "There are only two scenarios: How much of a lift does it give us to win? Or, can we regroup and be ready to play the Islanders if we lose?"

Well, can they?

"We're a little depressed today," said Craig Laughlin, after scoring twice in the 5-3 loss. "But we'll put that depression out of the way tomorrow and get ready to knock out the Islanders. The second season starts now."

Actually, Wednesday. Be there, or be square.

These Capitals, they're heartbreakers, aren't they? They tease you with a 2-0 lead in the first period here, just as they teased you with that 2-0 lead in games over the Islanders in the playoffs last year. They get you thinking that maybe this time it's for real, it's the full-length mink, the flawless diamond, the full house on a pat hand. Then someone squeezes them until they give it back, and what are you holding but a fistful of air?

The Capitals didn't want to play the Islanders, which is understandable for three reasons. First, the Rangers aren't as good a hockey team as the Islanders, let alone the Capitals. Second, the Capitals, although they swear they're beyond the so-called Islanders Jinx, are not necessarily beyond the so-called Islanders Jinx; they've played the Islanders three times in the playoffs and lost each time, including last season's grisly finale when the Capitals led two games to none, and, needing one more, were swept away three in a row. And third, the Islanders are such a physical team that even if the Capitals were to finally beat them, how high a price would it extract? Remember that Bengt Gustafsson and Mike Gartner already are sidelined, and perhaps now Bob Carpenter will join them there.

Winning here would have meant so much to the Capitals: the Rangers instead of the Islanders; home ice all the way to Edmonton; getting off the schneid in Philadelphia, where the Capitals now face the possibility of four games in the divisional final -- should they get that far. But most important, winning this game would have given the Capitals that banner, the symbolic proof that they had, indeed, won something. Statistically, the Capitals had their best season: more points, more wins than ever before. But what do they have to show for it? "You want something out of 80 games," Rod Langway said on Saturday night. "You don't want to go 80 games and get nothing." The banner, if it is to come, must now come the hard way, over the backs of both the Islanders and the Flyers.

Beat the Flyers this one time and there would have been no more questions about the credibility of a team that could get itself to the big one, but couldn't win it. Lose, and all you get are second-guessers and Billy Smith. "Playing the Rangers would be a lot different than our friends on Long Island," Laughlin said. Then, ever the optimist, he added, "They've beaten us three times in a row. It might be nice to beat them for a change. We've proven all year we're a better team, so why can't we prove it in the playoffs?" A fair question, the only relevent one facing the Capitals right now. It's one thing to say you know you can beat someone. It's quite another to actually do it.

"Nothing changes," Poile said resolutely after the game. "We're going to play on Wednesday. We knew that all along." Walking briskly, his words fell on straining ears, perhaps even out of harm's way.