President Clinton is turning down invitations to testify in the Monica Lewinsky investigation, but a judge says prosecutors' interests are important enough to compel two aides to answer questions despite a valid claim of executive privilege.

"If there were instructions from the president to obstruct justice or efforts to suborn perjury, such actions likely took the form of conversations involving the president's closest advisers," U.S. District Judge Norma Holloway Johnson said in declaring that Clinton confidant Bruce Lindsey and presidential adviser Sidney Blumenthal must testify in the Lewinsky probe.Yet the judge, in a 34-page decision made public Wednesday, concluded that a president's conversations with aides about an investigation of private conduct can be covered by executive privilege, including discussions involving Hillary Rodham Clinton.

"The president does need to address personal matters in the context of his official decisions," the judge wrote.

But even if the conversations are covered by executive privilege, Whitewater prosecutor Kenneth Starr proved that his need for the information was greater, Johnson wrote.

Prosecutors continued to press ahead with their investigation, summoning presidential friend Vernon Jordan for a third round of testimony before the grand jury in Washington. Jordan, who helped Lewinsky find a lawyer and a job, entered the courthouse without comment. He gave two days of testimony in April and for one day in May.

Johnson's decision earlier this month, while not issued publicly, had been known, and Wednesday's document release detailed her thinking.

Clinton, who just four months ago vowed to present the facts in the Lewinsky matter, saying it was not sexual, has declined as many as four or five invitations since February from Whitewater prosecutors to testify in the investigation, The Associated Press has learned.

Clinton's lawyers have given various explanations in declining to give testimony, ranging from a busy schedule to White House distrust of prosecutors, according to sources familiar with the dispute. The sources spoke only on condition they not be named.

Lewinsky, holding her father's hand, arrived at a federal building in Los Angeles Thursday morning to give handwriting, fingerprint and voice samples.

"My daughter is a pawn. Kenneth Starr is trying to use her as a pawn to get the presidency. It is unfair. It is totally un-American," her father, Dr. Bernard Lewinsky, told a crush of reporters surrounding them as they entered the building.