Republican National Committee Chairman Jim Nicholson went to conservative commentator Patrick J. Buchanan's McLean home yesterday to make the case that Buchanan should stay in the GOP, rather than seek the Reform Party presidential nomination. But there was no indication from either side that Buchanan had been swayed.

The two principals said little about the tone of the meeting, but one informed source said, "There's no reason to think anything has changed." Buchanan, who has been making his third try for the Republican nomination, has made it increasingly clear that he believes the party is determined to back Texas Gov. George W. Bush, whose views on trade and foreign policy, Buchanan says, are indistinguishable from the Clinton-Gore administration's.

Nicholson said he had asked Buchanan "to consider very carefully before taking any action that could in any way help Al Gore or Bill Bradley extend the Clinton-Gore era for another four years."

Nicholson said he reminded Buchanan of the Supreme Court appointments the next president may make and "asked him to think of President Reagan" and stay with the GOP.

Bay Buchanan, the candidate's sister and campaign adviser, said she would add nothing to Nicholson's statement. A source said Nicholson had indicated that he was simply "doing his duty" as party chairman in trying to prevent a Buchanan walkout, which could deprive the Republican nominee of votes. "There was no pleading, no kissing of rings," this source said. "Nor was he kicking Pat out the door."

Bauer to Deny Rumors of Affair

Gary L. Bauer, a Christian right candidate for the Republican presidential nomination, will hold a news conference today to deny rumors that he has had an affair with a campaign staffer. He reportedly plans to accuse Steve Forbes's campaign organization of spreading the rumors.

No evidence has emerged to support the rumors, and Bauer told the San Francisco Chronicle this week that the rumors were "disgusting."

"It's outrageous. It's trash-can politics," Bauer said. ". . . My wife and I have been married for 27 years. We have three children. I have been loyal to her, and she's been loyal to me all those years."

Bill Dal Col, Forbes's campaign manager, said: "Anyone in this campaign who speaks negatively or spreads vicious rumors [about the opposition] has been told from day one they would be fired."

The Front-Runner's Fitness

Except for a little knee and back stiffness, Texas Gov. George W. Bush is in "excellent" condition, according to a medical report released by his campaign yesterday.

Bush's doctor also shed some light on the drug question that has dogged the candidate in recent months. He didn't answer whether Bush has ever used drugs, but he did assure the public that he has never been treated for it.

"He has totally abstained from alcohol during the past 13 years," said physician Kenneth H. Cooper of Dallas. "He has no history of any alcohol, drug, mental or psychiatric treatment or rehabilitation. He follows a diet which is low in fat."

Bush has seen Cooper annually since 1989 and last saw him on June 17. "In general, his health has been excellent," Cooper said of Bush, who runs three to four miles five times a week.

In his last physical exam, Bush's body weight, 192 pounds, was normal for a 6-foot-2-inch, 53-year-old man. He passed the blood pressure test with flying colors. His cardiovascular fitness and blood lipids were "outstanding." And his lungs, prostate and other vital organs were just fine.

Staff writers Terry M. Neal and Thomas B. Edsall contributed to this report.

CAPTION: Pat Buchanan, still Reform-minded?