President Clinton's defense of his private conduct this year has endangered more than his reputation and credibility. The legal battles he has fought to avoid acknowledging that his behavior with Monica Lewinsky was inappropriate may have eroded presidential power and prerogatives for future presidents, say legal experts, constitutional scholars and political scientists.

The precedents set by court decisions rebuffing Clinton's efforts to halt a sexual misconduct suit by Paula Jones and prevent close aides and bodyguards from testifying before a federal grand jury investigating the Lewinsky matter have profound implications, experts say. Among them are these:- Presidents can now be sued for private conduct while still in office.

- Government lawyers may be compelled to disclose advice they provide to presidents.

- The notion that executive privilege protects a president's conversation with his advisers has been restricted.

- Members of a president's personal security force can be called to testify about his or her movements, actions and habits.

And Clinton voluntarily set a precedent, as the first president to testify before a grand jury investigating his own actions. One potential battle, over whether a prosecutor can require a president to appear by issuing a subpoena, was avoided - at least for now - when Clinton agreed to testify. But Starr has told the president that he still might subpoena him to compel testimony about matters Clinton declined to discuss.

Now many of those who ponder the impact on the institution fear serious consequences, including the potential for more lawsuits against presidents in office, inhibitions about giving presidents candid advice, disinclination to write memorandums or diaries, and difficulty recruiting quality advisers because of the risk of large legal fees.

"It's just been a disaster for the presidency," said Harold Bruff, dean of the University of Colorado Law School.