Everybody wants to know which party leader will step forward and bring the Democratic presidential campaign to a conclusion. I think we already know the answer, or at least a good part of it: House Speaker Nancy Pelosi.

Today, Pelosi appeared on ABC's "Good Morning America," where she made her most specific comments yet on how she envisions the Democratic race ending. While she conceded that superdelegates were technically free to vote their conscience, she reiterated the position she'd stated earlier: that superdelegates should back whichever candidate wins the most delegates from the primaries and caucuses. She also explained when she thought the contest should end--maybe not before the primaries are over, but not long afterwards, either:

The election has to run its course. For all that I have said about respecting the will of the people, the inference to be drawn from that is that we have to continue the election in terms of hearing from the people. ... I do think it is important to get behind one candidate a long time before we go to the Democratic convention if we expect to win in November."

This seems to be the emerging party line, so to speak. If necessary, wait until June 3, when Montana and South Dakota hold their contests. But then pick a winner shortly thereafter.

Some will complain waiting that long is dangerous--that, as my colleagues Jonathan Chait and Noam Scheiber have argued, such an extended race might seriously wound the eventual nominee (which, presumably, would be Barack Obama). I'm not so sure of that, for reasons I'll explain soon.

As a matter of political reality, though, I'm not sure there's a better option. If Clinton continues to win big contests (like Pennsylvania and Indiana) and the party leaders intervene anyway, Clinton and her surrogates would cry "count the votes"--that, as long as there's even a slim chance she can overtake him in either the popular vote or committed delegates, the race should go on. At least some Clinton supporters, including those who might entertain the thought of embracing McCain if Obama is the nominee, would agree with that argument. And, as far as I'm concerned, they'd have a point.

Unfortunately, if Clinton continues to win big contests, forcing a conclusion to the race may be difficult even after June 3--which really would be disastrous. That is why Pelosi may prove so pivotal. She is, after all, the most powerful elected Democrat in the country. She can wield influence by making public statements, by leveraging her powers as Speaker of the House, and by directing significant amounts of campaign money. Nobody else in the party hierarchy can do that. Among the party leaders, I suspect, only Al Gore has similar power. (And his comes almost entirely from his moral authority.)

Pelosi has one other asset that sets her apart from the rest of the party elders. She's a woman. If Pelosi is the one saying the race is over, it will be hard for Clinton to invoke one of her most powerful arguments: that "the boys" are trying to push her out of the race. (And I say that as somebody who thinks gender bias has definitely played a role in this campaign.)

Edit: I originally wrote that Puerto Rico held the last primary, on June 7. But Puerto Rico recently moved its contest to June 1. Thanks to reader AlanSP for letting me know. (Not sure how I missed that development.)

--Jonathan Cohn