Mr Kenneth Starr, the independent counsel who is investigating President Clinton's relationship with Ms Monica Lewinsky, has publicly raised for the first time the possibility of the impeachment of the President.
Mr Starr's reference to impeachment comes in a brief to the Supreme Court where he complains about attempts by Mr Clinton and his lawyers to delay his investigation. Mr Starr has set nerves on edge at the White House by saying that only disgraced former President Nixon has used such tactics.
Another development which signals danger for President Clinton has been the decision by Ms Lewinsky to replace her loquacious California lawyer, Mr William Ginsburg, with two of Washington's most skilled criminal defence lawyers, Mr Jacob Stein and Mr Plato Cacheris.
Observers see this move as likely to lead to an agreement between Ms Lewinsky and Mr Starr whereby she would testify about her relationship with President Clinton in return for immunity from prosecution for perjury. Mr Ginsburg had failed to secure such immunity for the former White House intern.
Mr Starr has been investigating since last January to find if the President lied about his relations with Ms Lewinsky and encouraged others to perjure themselves or obstruct justice.
Both the President and Ms Lewinsky have made sworn statements denying any sexual relationship, but she has contradicted this in conversations with a former colleague, Ms Linda Tripp, which were secretly taped.
In his latest submission to the Supreme Court urging it to expedite its review of President Clinton's claims of privilege, Mr Starr says: "We will be blunt. The nation has a compelling interest that this criminal investigation of the President of the United States conclude as quickly as possible - that indictments be brought, possible reports for impeachment proceedings issued and nonprosecution decisions announced."
A federal judge recently rejected claims by the President that his conversations with senior White House aides about Ms Lewinsky are covered by executive privilege. The judge also rejected the claim that secret service agents guarding the President should not be allowed to testify. The President has appealed against both rulings and Mr Starr now wants the Supreme Court to give its final ruling without waiting for the appeals to go through a lower court.
As an independent counsel, Mr Starr will have to make a report to Congress indicating if he believes President Clinton has committed an impeachable offence. It would then be up to Congress to decide whether to go ahead with the impeachment procedure.
With the President's high job approval rating, Republican politicians facing re-election next November are said to be reluctant to be faced with a possible impeachment decision which would antagonise voters. The booming economy under President Clinton would also discourage his opponents from moving to replace him.
The White House called Mr Starr's latest moves "an act of public relations, not a work of law". A legal affairs spokesman, Mr James Kennedy, said that "Mr Starr is trying to end-run the rules and leapfrog the legal process".