John Keker, the lawyer prosecuting Oliver North, has a reputation for intuitively making the right move in a courtroom.

In a civil suit, lawyers for a bank abruptly asked one of Keker's clients whether he would waive the attorney-client privilege of confidentiality.Reacting to the unorthodox request, Keker quickly said his client - an investor who says he had been defrauded - would agree to a waiver if the bank was willing to waive the same privilege covering conversations with its attorneys. The bank backed down.

Representing an insurance company accused of overcharging its customers, Keker on cross-examination asked an expert witness to select from a stock of well over 100 files the one he considered to be the most egregious example of overcharging.

Robert A. Van Nest, a partner in Keker's San Francisco law firm, recalls that Keker spent a minute familiarizing himself with the contents of the file selected by the expert and "then proceeded to tear the witness apart."

"Two things about John," said Van Nest, his tenacity and his intuition. "He doesn't let a point drop. He will fight all the way to whatever is there.

"He's remarkably intuitively skilled in a courtroom. It's a great athlete's intuition, to know where the ball is and where everything is on the field. John has that kind of intuition. He has an ability to respond to the evidence."

Keker's ability "to kind of sense where the witness is going" is "a rare skill in today's lawyer," said Van Nest. "So many of us take deposition after deposition and there's nothing to predict."

Keker's weaker points? "He has as many weaknesses as the San Francisco 49ers," said Van Nest.

The North case is Keker's first as a prosecutor, but his abilities as a defense lawyer translate easily to the other side, said William T. McGivern Jr., chief assistant U.S. attorney for northern California.

"He's always been aggressive and he can bring that aggression to the prosecution side," said McGivern. "He's aware of the moves of a defense lawyer, having been one himself."

In short, Keker "can try a case, there's no doubt about that," said McGivern, who as a prosecutor has been involved in several cases in which Keker has been a defense attorney.

A Vietnam War veteran who served in the Marines and was wounded in combat, Keker is a graduate of Princeton University and Yale Law School and a founding partner of Keker & Brockett in San Francisco.

He has successfully defended moviemaker George Lucas in a civil suit and won a case in which his client, a San Francisco society figure and architect, was accused of vehicular manslaughter.

After the Iran-Contra affair erupted in 1986, Keker sought work with independent counsel Lawrence Walsh.

"John felt there was an important lesson here for Americans who care about the democratic process and he was intent in participating in the investigation for that reason," said Van Nest. He said Keker had concerns that those involved appeared to have been "running foreign policy without the consent of the people."

"The political and legal implications struck me as enormous," Keker said of the Iran-Contra episode in an interview last year with The Los Angeles Times.

Keker, 45, has more than 15 years as a trial lawyer and relishes the role. "When you go to court," he told the Times, "you get a chance to be a hero, which is a thing that most people repress the desire for. You also get a chance to fail enormously.

"That sort of edge is something that people who are trial lawyers usually like. You get a chance to do the right thing. You get a chance to do it in a stylish way."