Rep. Charles Joseph Scarborough, a freshman Republican from the Florida panhandle, marked the 50th anniversary of the United Nations last month with an against-the-grain gesture: He introduced a bill that would end U.S. membership in the world body.

A four-year transition period and out, period. No permanent seat on the Security Council. No blue-helmet peacekeeping missions. No money. Except for the International Atomic Energy Agency, the United States would cease to participate in all U.N.-sponsored activities and the United Nations would leave New York for parts unknown.

Hold the chuckles. Scarborough, 32, keeps a coonskin hat in his office and likes to wear jeans on Fridays, but he wants it known that he is not, in his words, a "knuckle-dragging isolationist."

On the contrary, he described himself in an interview as a thoughtful internationalist who has concluded that the United Nations has outlived whatever usefulness it may have had. Just as European alliances formed at the Congress of Vienna after the Napoleonic wars dissolved as circumstances changed, Scarborough said, the time has come to scrap the United Nations and start over with an alliance of "like-minded liberal democracies."

In his view, the United Nations is a bloated, corrupt organization incapable of reform because its structure is no longer relevant and many of its members are dictatorships hostile to the principles upon which the world body was founded.

He said it is absurd that Britain and France -- which received permanent Security Council seats and veto power because they controlled vast colonial empires in 1945 but are second-tier powers today -- should retain those Security Council seats while nations such as Germany and Japan are excluded.

The United Nations has had 10 years to respond to "reform or die" legislation sponsored by Sen. Nancy Landon Kassebaum (R-Kan.) in 1985, Scarborough said, and nothing much happened. "Anybody who would suggest today that the U.N. is better and more efficient and more effective than it was when it received that ultimatum in 1985 has a skewed view of history over the past 10 years," Scarborough said.

He said he knows his bill is not going to be enacted "in this century," but he said passage of a law is a secondary objective. His goal, he said, is to give intellectual respectability to the idea that a new international structure is needed. He aims to show that espousing the end of the United Nations is a responsible position, given the U.N.'s acknowledged problems, and is not "the ranting of a conspiracy theorist or a member of the black helicopter crowd."

He said it is a "false dichotomy" to argue, as many in the foreign policy establishment do, that "either you support the U.N. or you're an isolationist. . . . We're not talking about being isolationists, we're talking about a network of continuing alliances with liberal democracies."

Scarborough's incipient campaign got a boost last month when the New Republic magazine published a long article titled "Twilight of the U.N." that advanced arguments similar to his.

The article quoted a recitation by renowned Israeli diplomat Abba Eban of a long list of crucial global developments since World War II in which the United Nations had no part, including termination of the Berlin blockade, Algeria's independence from France, U.S.-Soviet arms control agreements, the Panama Canal settlement and the Egyptian-Israeli peace treaty.

In testimony before a House subcommittee on Oct. 26, Scarborough cited a similar list and added the Marshall Plan and the reunification of Germany.

"In which of these great historic achievements did the United Nations play a critical role? The answer is, not one," he said. "The U.N. has been a passive bystander, an expensive toy but hardly a critical tool."

Scarborough noted that longtime supporters of the United Nations -- including Kassebaum, Rep. Lee H. Hamilton (D-Ind.) and the U.S. ambassador to the U.N., Madeleine K. Albright -- have said the United Nations must be reformed and reorganized. Kassebaum and Hamilton said in a joint article in The Washington Post last month that "the United Nations as it exists today is not sustainable. . . . The task for our generation is to ensure that the machinery of the United Nations works. Today it does not."

Scarborough said he agrees that the "machinery" does not work. But in his opinion, it cannot be made to work and so should be abandoned.

Scarborough, an engaging, preppy lawyer and Sunday school teacher, was propelled into office by the GOP landslide of 1994, the first Republican to represent northwestern Florida in this century. He has generally marched in step with his fellow freshmen to the cadence called by House Speaker Newt Gingrich (R-Ga.), but he was one of only 10 Republicans who voted against the GOP's budget-balancing bill.

He said dismantling the United Nations and replacing it with a new international security structure was "not on the front burner" of issues in his district but the war in Bosnia was. It was the performance of the United Nations in that conflict, he said, that started him thinking about whether the organization was capable of dealing with post-Cold War conflicts. CAPTION: REP. C. JOSEPH SCARBOROUGH