President Clinton faces a crisis point this week in the investigation into his relationship with Ms Monica Lewinsky and whether he urged her to commit perjury about it.
It has now been confirmed that he is the first US president to be served with a subpoena to testify into alleged crimes concerning himself. The subpoena summons him to testify this week to the grand jury investigating the matter under the Independent Counsel, Mr Kenneth Starr.
Mr Clinton's lawyer, Mr David Kendall, has been negotiating with Mr Starr over President Clinton's response to the subpoena.
Mr Clinton is said to have decided he will not appear before a grand jury in a Washington courthouse, but he may be ready to give videotaped testimony in the White House which could be later shown to the grand jury.
But if Mr Clinton claims that Mr Starr has not powers under the Constitution to subpoena a president, the case would go the Supreme Court. A decision would not be given until later this year after the mid-term elections in October.
Legal experts say that the Supreme Court would be unlikely to uphold the President's refusal and recall the decision in July 1974 which made the then president, Mr Richard Nixon, obey the subpoena to turn over tapes of his conversations in the Oval Office and which led to his resignation.
Mr Starr is now regarded as wrapping up his investigation which began last January after allegations that Ms Lewinsky had a sexual affair with President Clinton and later lied about it under oath on his advice.
Mr Clinton has denied under oath that he had sex with Ms Lewinsky while she was a White House intern and later worked at the Pentagon. The President has also denied that he asked her or anyone else to commit perjury as part of a cover-up.
Mr Starr will at some stage make a report to Congress on whether Mr Clinton has committed actions for which he could be impeached.
Congress would then have to decide on whether or not to impeach the President. Impeachment is very rare, and was last discussed but not enacted over President Nixon.