"It is time for this to end, here and now," White House counsel Pat Cipollone said in his closing remarks in the Senate on Tuesday.
Cipollone has repeatedly criticized what he says is a dangerous "shell game" launched by Democrats to remove Trump from office, reports Efe news.
Earlier Tuesday, one of Trump's personal lawyers, Jay Sekulow, argued that the case against the President was weak and that he had been impeached over mere policy differences, adding that if he was removed from office it would set a dangerous precedent.
"Future presidents - Democrats and Republicans - will be paralysed the moment they are elected. Before they can even take the oath of office," he said. "The bar for impeachment cannot be set this low."
The defence attorneys' brief final arguments contrasted with lengthy sessions last week in which House of Representatives impeachment managers (prosecutors) led by California Democrat Adam Schiff insisted there was overwhelming evidence of Trump's guilt.
Now that both sides have concluded their opening arguments, the senators, who are serving as jurors in the trial, will have two days - Wednesday and Thursday - to present their questions in writing to either the prosecution or defence via Supreme Court Chief Justice John Roberts, who is overseeing the trial.
A crucial day then looms on Friday, when the Senate will debate and then vote on whether to allow additional evidence and witnesses.
Democrats say it is essential that new materials be introduced, while Trump's attorneys and his Republican allies in the Senate oppose the idea. The vote of a simple majority will decide that matter.
Since Republicans have a 53-47 majority, that means that Democrats need the support of four Republican senators to prevent the trial from ending quickly with a vote on the two articles of impeachment.
The focus now is on four Republican senators who may support additional evidence and witnesses: Mitt Romney (Utah), Susan Collins (Maine), Lamar Alexander (Tennessee) and Lisa Murkowski (Alaska).
One key witness who did not testify during the House's impeachment probe but has said he will appear before the Senate is Trump's former National Security Adviser, John Bolton.
That testimony could be harmful to Trump because according to excerpts from Bolton's upcoming book - published onSunday by the New York Times - he said the President told him he wanted to withhold congressionally approved military aid for Ukraine as a means of pressuring that country to announce corruption investigations into former Vice President Joe Biden and his son, Hunter.
The excerptdirectly concerns the "abuse of power" charge against Trump, who allegedly used the power of his office to solicit "the interference of a foreign government, Ukraine, in the 2020 US presidential election".
The accusation stems from an allegation that during a phone call last July Trump sought personal political gain by improperly pressuring Ukrainian President Volodymyr Zelensky to publicly announce an investigation into the alleged interference years ago of Joe Biden, a leading contender for the 2020 Democratic presidential nomination, in a probe of his son's business dealings in Ukraine.
The second article of impeachment accuses the President of "obstruction of Congress" for directing executive branch agencies, offices and officials not to comply with subpoenas seeking documents and testimony deemed vital to the House's inquiry.
Trump is only the third US president to be impeached.
Under the US Constitution, the approval of articles of impeachment in the House is to be followed by a trial in the Senate, where it takes a two-thirds majority to remove the president from office.
Due to Republicans' control of that upper chamber, it is considered highly unlikely that Trump will be convicted.
( With inputs from IANS )