Mr Clinton's personal lawyer, David Kendall, focused on the obstruction of justice charge against Mr Clinton, attacking the evidence put forward by the prosecution.

He said the obstruction charge was "based on circumstantial evidence, and that is at best profoundly ambiguous".

David Kendall's opening statements in the President's defence

He accused the impeachment prosecutors of ignoring other evidence which would have exonerated the president. There were certain facts, he said which House prosecutors "simply ignored in their attempt to fit some of the facts into a sinister pattern".

But it was left to long-time Clinton friend and former senator Dale Bumpers, to make the closing address for Mr Clinton's defence.

In an emotional and personal speech, he urged senators to recognise the personal anguish suffered by Mr Clinton as a result of his "terrible moral lapse". He said the punishment of removing him from office would pale in comparison with this.

Dale Bumpers: "The people are calling on you to rise above partisanship"

Mr Bumpers focused on Mr Clinton's achievements as president and warned that the impeachment proceedings could be dangerous to government and the political process, resulting in "havoc".

"You have taken a solemn oath to be fair and impartial," he told his former colleagues in the chamber. "I know you all; I know you as friends, and I know you as honorable men, and I am perfectly satisfied to put that in your hands, under your oath," Mr Bumpers said.

Next stage looms

David Kendall: Certain facts "simply ignored"

Senators, meanwhile, have been preparing for the next stage of the trial, when they will be able to put questions to each side after the defence presentation. Leaders of both parties have said they would seek to approve questions or consolidate similar queries.

The question of whether witnesses will be called remains a contentious issue in the Senate. On Wednesday, senators held separate party meetings and Republicans emerged sounding more sure they will seek to call at least some witnesses during the trial to resolve conflicts in testimony.

A BBC correspondent in Washington says the defence appears to have already done enough to rally Democrat senators and unless something unforeseen happens, Mr Clinton will not be convicted.

In their second day of defence arguments, White House Special Counsel Gregory Craig and Deputy Counsel Cheryl Mills attacked the impeachment charges passed by the House of Representatives against Mr Clinton over his conduct in the Lewinsky affair as vague and unfounded.

The BBC's Stephen Sackur: "Some believe the White House lawyers have done a very good job"

In the Senate, Mr Craig said the allegations of perjury were not legally or structurally sound enough to "remove this or any president from office".

"If you convict and remove President Clinton, on the basis of these allegations no president of the United States will ever be safe from impeachment again," he warned the hushed Senate chamber.

Cheryl Mills - a 33-year-old African American - was the first woman to address the trial.

As his lawyers continued their defence, President Clinton's already strong standing in the polls was boosted by his State of the Union Address, in which he focused on the American people's problems - but made no mention of his own.