The White House on Thursday wrapped up its defence, which followed a three-day prosecution by 13 House-appointed trial `managers,' set the stage for a tough fight on Monday when lawmakers were likely to take up motions to dismiss and call witnesses.

The managers continued to press for witnesses, which could prolong the trial for months. The list could include Monica Lewinsky, Clinton advisor Vernon Jordan, and the President's secretary Betty Currie.

But there were signs the tide could be turning toward bringing the first such trial in 131 years to a quick end.

Clinton's defenders wrapped up arguments at his impeachment trial with an ex-Senator's urgent plea to his former colleagues not to oust Clinton over a ``moral lapse''.

Clinton ``suffered a terrible moral lapse, a marital infidelity, not a breach of the publictrust, not a crime against society,'' said former senator Dale Bumpers, who highlighted their quarter-century of friendship.

Bumpers tarred Clinton's affair with Monica Lewinsky as ``indefensible, outrageous, unforgiven (and) shameless,'' but warned the impeachment trial was ``dangerous to the political system.''

``If you vote to convict... you're going to be creating more havoc than he could ever possibly create,'' he told his former colleagues, hearing the second Presidential impeachment trial in US history.

The White House hoped momentum from its often sharply worded but methodical three-day case would rally its Democratic Senate allies and wavering Republicans to bring the trial to a swift close.

`If the Republican leadership feels the votes are not there for conviction and frankly that's the way they feel, then they have a responsibility to wrap this up,'' said Democratic Senator Patrick Leary.

And Republican leaders, who have repeatedly said that the proceedings require at least a fewwitnesses, said that step was still necessary while showing signs of increased pressure to close the case.

``I do know that there's quite a lot more talk about; let's get this over with," said Republican majority leader Trent Lott, who cautioned that not calling witnesses was ``a big leap of faith that I'm not sure the Senate's ready to take yet.''

Few believe that the two-thirds majority needed to convict Clinton and remove him from office will materialise in the Senate, where Republicans hold a 55-45 edge.

Senators on Friday will pose their questions through US Chief Justice William Rehnquist, who was presiding over the impeachment trial.

Republicans have some 70 questions so far, said a spokesman for Lott, who said questioning would probably run through Saturday.

Lott himself praised Bumpers' address, telling reporters: ``Dale always gives an excellent speech."

The former Senator's often emotional tone contrasted sharply to the legalistic arguments of defence attorneys enlisted to fend offobstruction of Justice and perjury charges stemming from the Lewinsky scandal.

The President's private lawyer David Kendall earlier derided what he termed ``plainly defective'' charges relying on ``myths'' and fired occasional sarcastic broadsides at the prosecution's case.

Citing Lewinsky's testimony that ``no one ever asked me to lie, and I was never promised a job for my silence,'' Kendall asked trenchantly: ``Is there something difficult to understand here?''

And taking on a criticism frequently levelled at Clinton, he stressed, ``It's not legal hair-splitting to raise available defences or to point out gaps in the evidence or to make legal arguments based upon precedent.''

Clinton's lawyers on Wednesday charged that the case against the president comprises ``trivial'' charges an ignores exculpatory evidence, and urged Senators to let him keep his job.