Mr. Perle, the neoconservative and former adviser to Donald Rumsfeld, offered to walk through his local Costco, pointing out the products that he said were increasingly drawing D.C. power shoppers like himself. That Richard Perle? The gourmand with a home in Provence who once dreamed of opening a chain of souffle restaurants?

Yes, Mr. Perle proudly shops in Costco's concrete warehouses stocked with three-pound jars of peeled garlic and jumbo packs of toilet paper. And he has no problem serving the store's offerings to dinner guests. "Because it should have been Dean & DeLuca?" he asked, sounding half incredulous and half amused. "I really think there's a socio-cultural thing here, and people are entitled to their pretensions." As a recent article in Vanity Fair lamented, the days of glamorous Washington dinner parties are long gone. Indeed, some hostesses today aren't above serving Costco salmon, nicely dressed up with a dollop of creme fraiche.

Mr. Perle said he shopped at Costco once a week when he was in town, and at a dinner party he held recently for several colleagues and friends, most ingredients were from there - the beef for his daube a la Provencal, the limes for his lime souffle. The salmon for gravlax - also from Costco. He said he always received compliments, and he always got double takes when he told his guests where he shopped. He's not the only D.C. host or hostess to go big box. "I do it - Costco all the way," said the writer Sally Quinn, who is known for the power salons she puts on with her husband, the former Washington Post editor, Ben Bradlee, at her Georgetown town house. "I just started."

Ann Jordan, the wife of Vernon Jordan, also calls herself "a big fan" and says she has used Costco food for parties, especially for the fund-raisers she held during the Clinton years. Ellen Bennett, a fine art photographer and the wife of Robert S. Bennett, President Clinton's personal lawyer in the Paula Jones case, has thrown an open house "Costco party" each Christmas since 2004. "Pigs in blankets, salamis, salmon, shrimp, pate, cheese," said Mrs. Bennett, remembering her parties. Juleanna Glover, a lobbyist and former aide to Vice President Dick Cheney who is also known as a hostess, was an early convert. And, she added, almost as if confiding a secret, "You recognize the brownies and black and white cookies at some of the most prominent individuals' homes." Susan Lacz, chief executive of Ridgewells, the largest catering company in the Washington area, said she knows the trend all too well. "My gosh, it drives me crazy," she said. "Some of the people I hear are going to Costco, I think, 'Oh, you must be kidding me.'"