Former Navy secretary James H. Webb became the second high-ranking Republican to bolt his party and condemn U.S. Senate candidate Oliver L. North, appearing at Arlington's Iwo Jima Memorial yesterday to accuse North of chronic lying.

Webb and five other high-ranking Navy or Marine Corps veterans stood side-by-side with Democrat Charles S. Robb and portrayed the Virginia Senate race as a battle between two Marine veterans, one of whom they accused of betraying the honor of the Corps.

In often emotional tones, the veterans accused North of falsely disparaging Robb's service record, inflating his own resume and violating a basic tenet of military service by lying to Congress during the Iran-contra affair.

Webb also called several senior members of his own party hypocrites, accusing them of endorsing North in public while criticizing him in private.

Webb, a classmate of North's at the Naval Academy in Annapolis, said many military people who know North have reservations about him but have been reluctant to come forward.

"We have marveled at the exaggerations and the missteps he has brought to the public arena," Webb said. "Most of us have remained silent. But it has become imperative for anyone who respects the Marine Corps as an institution to say, 'Enough is enough.' "

Webb and Sen. John W. Warner (Va.) are the only two senior Republicans who have taken public stands against North to date. Warner broke bitterly with North this spring and is supporting independent candidate J. Marshall Coleman.

Although he refused to name names, Webb heaped contempt on high-ranking GOP activists who have backed North's bid in hopes of securing a Republican majority in the Senate. Among those who have expressed reservations about North but have rallied to his cause are Senate Minority Leader Robert J. Dole of Kansas and former secretary of state James A. Baker III. Both are possible presidential candidates in 1996.

"I can see no greater corruption of this {political} process than to see people who I know privately condemn North while publicly endorsing him," Webb said.

"These people who do come forward though political expediency endorse that kind of conduct" North displayed during Iran-contra.

The Republican leadership also was harshly criticized by Lawrence Walsh, the special prosecutor who took North to court during the Iran-contra scandal.

During an address last night to a University of Virginia debating society, Walsh said Republicans in Congress first made North a scapegoat, and now seem to be seeking his future support.

The entire Congress "blew it" by granting North immunity, Walsh added, saying immunity should be extended only after a witness has made it clear he is willing to share valuable information.

"The last thing you want to do is grant immunity to someone who is going exculpate everyone," Walsh said. He also said there was no question North lied to Congress.

Earlier in the day, in an interview with New York Newsday, Walsh accused Dole, Baker and others of a "shocking display" of hypocrisy for supporting North.

"To see that group coalescing around North -- it's a party problem," Walsh said.

A spokesman for North, Mark Merritt, dismissed Webb's remarks about North as a "petty and juvenile" attempt to settle an old score between the men that dates back to Annapolis.

An underdog North defeated Webb in a closely contested championship boxing match that has become a part of Naval Academy folklore; in a best-selling novel Webb wrote, a fictional boxing match somewhat similar to the one he lost plays a prominent role.

"Jim Webb is trying to win in the political arena what he wasn't able to win in the boxing arena 30 years ago," Merritt said.

"If {Webb and others} are concerned about lying, they ought to ask Chuck Robb why he's masquerading as a liberal."

Webb acknowledges the old rivalry and said the issue kept him from speaking out sooner because he knew it would come up.

"If I had had any vendetta against North, I would have exercised it when I was secretary of the Navy," Webb said.

Among the five veterans who appeared with Webb and Robb yesterday, four described themselves as Republicans or Republican-leaning voters.

The only Democrat was Sen. Bob Kerrey of Nebraska, who won the Medal of Honor as a Navy Seal in Vietnam.

Kerrey bitterly condemned North for questioning Robb's military service record.

Last week North called Robb an "Eighth and I Marine," referring to the Marine Corps facility in the District that is used for ceremonial purposes; Robb served for 13 months in Vietnam. North later denied that he intended to disparage Robb's record.

"This isn't about who's the best Marine," Kerrey said.

"This is about who lied and who told the truth," Kerrey said. "Oliver North lied about Chuck Robb's record. We didn't lie about Oliver North."

Special correspondent Jeff Leeds contributed to this report from Charlottesville.