Even as the House was getting ready to vote down the president's contra aid package last evening, area Democrats were taking their party confidence to The Bank. The Bank in this case being the former savings and loan at Ninth and F streets NW, which has been converted into an elegant three-story club.

More than a thousand young Democrats packed the rooms to celebrate, perhaps prematurely, "The Retaking of the White House in 1988." Sponsored by various lobbyists and other sympathizers, the $25-per-person fundraiser was conceived as "a good party for the people who do all the work" in campaigns, according to Michael Colopy, a member of the celebration committee.

"We wanted to have it before the caucuses and the primaries because we're trying to keep as much good-spirited competition within the party as we can," Colopy said. "We want to remind everyone that we're one party, and to keep the spirit of competition as light as it can be."

Party unity was very much on the minds of those in attendance. "I think on the eve of battle," said committee member Nancy Jacobson, "we all stand united. It also shows," she added, surveying the 22- to 35-year-old crowd, "the Reagan administration doesn't have a monopoly on the young vote."

Ruby Anderson, a legislative associate with James Jordan Associates, admitted she hadn't even decided which candidate she preferred, but said matter-of-factly, "I know I'm going to vote Democratic."

"Any Democrat can beat any Republican this year," was the opinion of Jeff Peterson, director of government relations for the Distilled Spirits Council and a Richard Gephardt supporter. And Ciaran MacMathuna, a bartender at the Dubliner who just became an American citizen and is not yet eligible to vote, said, "If I could, I'd vote Democratic and I'd vote for Mike Dukakis because he's right on the issues."

The issue on Michele Manatt's mind was the contra aid vote. "I was in Nicaragua a month ago on a family vacation," she said. "It's a very distressing situation ... There are tremendous shortages ... I felt very uncomfortable there. They're very anti-American. We should let the peace process take its course, and if we continue to fund the contras, that peace process will not have a chance."

With the Iowa caucuses five days away, predictions of the winner were dominating many conversations. "I think my fellow Missourian Dick Gephardt will win," said former representative Jim Symington, "and if he does it's because he deserves it. He's worked long and hard."

"Simon will win in Iowa, and he will win in New Hampshire," announced Jack Evans, who is one of Illinois Sen. Paul Simon's campaign coordinators.

But the clear favorites among those present were Massachusetts Gov. Michael Dukakis and Tennessee Sen. Albert Gore, whose photographs during a slide show brought deafening cheers of approval. In his remarks to the group, Sen. John F. Kerry (D-Mass.), chairman of the senatorial campaign committee, made clear his judgments about the current ruling party: "The Reagan administration has more special prosecutors who are well known than they have White House staff who are well known," he said to applause and whistles. And "if Oliver North is a national hero, then Tammy Faye Bakker is Ronald Reagan's notion of Mother Teresa."

Kerry, not surprisingly, expressed supreme confidence in his governor. "If Dukakis wins {in Iowa}, it's all over."

And if he doesn't win in Iowa? "I think he'll win New Hampshire."

And in any case, come November, "I am absolutely convinced that a Democrat is going to win."

The upcoming campaign seemed to rekindle the combative instincts of the veteran Symington. But, amid all the enthusiasm, he issued a cautionary note, recalling the wisdom of his father, former senator Stuart Symington: "After a terrific cat fight, what do you have? More cats."