President Clinton's legal struggles now appear likely to redefine the powers of the presidency to a degree unseen since the momentous days of Watergate.
Over the course of Mr. Clinton's second term, a series of key court rulings have chipped away at legal defenses used by generations of chief executives in their dealings with other branches of American government.
In the latest such move, a federal judge has ruled that Clinton can't use the power of his office to keep prosecutors from raising certain questions with his senior aides.
Independent counsel Kenneth Starr's need to collect testimony for his obstruction of justice probe against Clinton outweighs the White House interest in protecting "executive privilege" confidentiality, according to Judge Norma Holloway Johnson.
The White House can still file an appeal on this issue with the Supreme Court. But if the ruling is upheld - an outcome many legal experts consider likely - it could diminish the usefulness of executive privilege for future occupants of the Oval Office.
"Executive privilege is best used as a bargaining device," says C. Boyden Gray, White House counsel for President Bush. "When you invoke it and use it in the courts you risk losing it."
Executive privilege isn't the only power of the presidency that has taken a beating in court in recent years. Most notably, one year ago the Supreme Court rejected the contention of Clinton's lawyers that presidents should be shielded from civil lawsuits while in office, to prevent the disruption of public business. The justices voted 9 to 0 to let the Paula Jones civil case proceed.
One aspect of the justices' reasoning - that such a case would be only a minimal distraction - was not exactly proved correct in subsequent months. Jones's case itself was not a strong one, according to the district judge who summarily dismissed it last month. But the foundation of the unanimous high court ruling in Jones v. Clinton was a reaffirmation of a bedrock US principle.
"The rule of law should not change based on who happens to be president of the United States," says Ronald Rotunda, a law professor at the University of Illinois and a consultant to independent counsel Kenneth Starr.
The president has also already lost on one other attempt to shield his private communications. Courts rejected his claim to attorney-client privilege in certain conversations with White House lawyers. While such a privilege exists with personal attorneys, government-funded lawyers are by definition servants of the public, the court ruled.
Neither Clinton nor his lawyers have spoken publicly about their claims of executive privilege. Indeed, the president has at times professed to know little about the matter.
But reports have indicated that the president's lawyers invoked executive privilege to try to preserve the confidentiality of communications from two top aides, Bruce Lindsey and Sidney Blumenthal. The discussions in question dealt with sex and perjury allegations involving former intern Monica Lewinsky.
Clinton is far from the first president to claim a need to keep communications with aides private. George Washington resisted turning over certain military documents to Congress. Thomas Jefferson resisted disclosure of a private letter that pertained to the treason trial of his former vice president, Aaron Burr.
But it was Richard Nixon that made the phrase "executive privilege" famous. Nixon declined to turn his White House tapes over to special prosecutor Leon Jaworski. He cited the need to keep communications with aides private, to ensure they would give him unvarnished advice.
The Supreme Court ruled in 1974 that executive privilege did in fact exist, despite the fact that the phrase appears nowhere in the Constitution But justices added that the value of this privilege should be weighed against the virtues of disclosing the evidence. It ordered Nixon to disclose the tapes. He resigned shortly thereafter.
White House mum
Officially, the federal court ruling in the Clinton executive privilege case is still under seal. Details of the arguments used on both sides thus remain largely unknown. At time of writing, the White House was maintaining public silence on the issue, and whether it would pursue its case to the Supreme Court. "We don't even know if there's been a decision," says White House spokesman Michael McCurry.
Still, Ken Starr may well have outlined the battle lines in a speech he gave last week on the general issue of privilege to a bar association meeting in Texas.
Presidents have a strong claim to keep discussions related to military or diplomatic matters secret, Starr said. The claim is weak when it relates "to a generalized interest in confidentiality."
Many analysts agree the Lewinsky matter is not the sort of issue executive privilege is intended to protect. "Their claim appears to be so weak it leads me to believe they are using it as a delaying tactic to protect themselves," says Mark Rozell, an American University law professor. Appealing the issue to the Supreme Court could delay its resolution for months or longer.
* Staff writer Warren Richey contributed to this report.