A virtual Who's Who of conservative Republicans turned out last night to celebrate the first anniversary of "The McLaughlin Group," a 30-minute television talk show with a panel of five media heavies that has been often referred to as the "conservative verion of 'Agronsky & Co.'"

And as most in Washington know: when a television opinion-shaper has a party, it's not an issue that invites prolonged debate. You just go.

"I confess the leanings are a little to the right," said Morton Kondracke, one of the liberals on the show and executive editor of The New Republic. "But that's not the difference between us and the Argonsky show. They're just dull."

"Got any scoops for me?" John McLaughlin, the show's moderator, whispered to presidential assistant Richard Darman.

"You know I'm not in that business," said Darman. "Don't you read Evans and Novak?" Inside joke. Darman has often been a victim of Evans and Novak. "I oughta get my own program," said Sen. Robert Dole (R-Kan.), surveying the high-order group gathered at decatur House. "I never get a crowd like this."

Among the 200 who hovered by the kiwis were Vice President Bush, White House Chief of Staff James Baker, presidential counsel Fred Fielding, presidental assistant Lee Atwater, Sen. John Warner (R-Va.), Sen. Robert Kasten (R-Wis.), White House director of communications David Gergen, EPA Administrator William Ruckelshaus, USIA Director Charles Wick and Energy Secretary Donald Hodel.

President Reagan sent McLaughlin a letter wishing him continued success, saying. "'The McLaughlin Group' reflects farsighted judgment and concern for public policy on the part of thoughtful elements of the private sector."

Bush was the night's star as cameramen swooped on him like they use to do for Alexander Haig. The timing wasn't particularly good, though. They seemed to catch him every time he started chewing. Finally, a thoughful photographer suggested the mob let the vice president swallow.

"Hey, I like you," Bush yelled to the photographer. Then they all clicked away.

Ruckelshaus slipped in and out quietly, his second consecutive night on the party circuit. He was sworn in last week.

"Oh yeah, I like being back -- a lot of action," he said.

Wick also slipped in. But he never slips in anywhere quietly.

"I just got back from Williamsburg on a Marine helicopter," he told a little semi-circle of people who had gathered around him. "That thing shook so hard, it cleaned all my jewelry."

During the Nixon years, McLaughlin was known as the Watergate priest -- a Jesuit who defended his boss right up until that sticky August in 1974. Soon after, McLaughlin left the priesthood, and last year surfaced with his well-regarded show.The show's other panelists are Robert Novak, Kondracke, Jack Germond and Patrick Buchanan.

"I never prepare for the show," quipped McLaughlin, "that would put me on unequal footing with my panel. I'm just the zookeeper, and you know how they can turn on you at any minute."

"It's a great deal more lively and less pompous that the Argonsky show," decreed Darman.

"I like it!" said Bush.

As the last crumbs of blue cheese and soggy pineapple were devoured by the thinning crowd, New Republic editor Hendrick Hertzberg looked about: "I've never seen so many reactionaries in one place in my life . . . So I'll move on . . ."