Washington may be the only city in the world where 10 sexy, slinky models dressed in leather hotpants, glued-on shirts and scarlet mini-skirts could walk into a room and be upstaged by Interior Secretary James Watt and national security adviser Richard V. Allen.

Last night, designer Gloria Vanderbilt brought her Murjani show to town to help raise campaign money for her distant cousin, maverick Rep. John LeBoutillier (R-N.Y.). The $200-a-head fashion delight netted LeBoutillier about $20,000.

"I wasn't the attraction here tonight," said LeBoutillier, at 28 the youngest member of the House. "This would work for any congressman. Everyone came to see the models and the clothes."

Not exactly. Washington being its business-as-usual self, the gaggle of Cabinet members, congressmen, lobbyists and White House aides who showed up at the Hyatt Regency Hotel virtually ignored the variously smiling and sulking models.

Except for Rep. Mickey Leland (D-Tex.), one of the token Democrats in attendance. He made a date with three of the models for 7 tonight at Stetson's, a country-western bar. Lori Esteep, 22, Cathay Bomar, 24, and Pamela Housman, 23, giggled feverishly, hanging on every last word Leland uttered.

Shortly, in came the embattled Richard V. Allen.

"Soon," he answered, when asked when he'll be back in the White House. "I think it'll be all over soon." Allen took a leave of absence from his post last week pending a Justice Department investigation.

"I just want to say that I'm 100 percent with you," said New York lawyer Roy Cohn, of McCarthy-era fame, saying hello to Allen.

"You're kind," said Allen. "You know, when I was a freshman at Notre Dame I can remember being sick in the infirmary and watching you on televison."

LeBoutillier couldn't thank Allen enough for coming. "I knew about him before he knew about us," said Allen. "You don't forget a name like LeBoutillier."

The neophyte from New York won his first election on a wing and a prayer and a $400,000 media blitz.

"It shouldn't be as tough a race this time," said the boyish-looking congressman. "But who knows?" He smiled. Gloria Vanderbilt smiled. And the sultry models continued passing out free samples of Murjani perfume to all the guests who were afraid to look.