- The proceedings come after the upper chamber voted to block new firsthand witnesses from coming to testify against the president.
- House impeachment managers, who act as prosecutors in Trump's trial, argued the Senate has a constitutional obligation to hear any relevant information pertaining to Trump's alleged misconduct.
- The president's defense team said the Senate didn't need to hear from any more witnesses while simultaneously claiming House prosecutors hadn't allowed for enough witnesses.
- Scroll down to watch the trial and follow Insider's live coverage.
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President Donald Trump's impeachment trial is expected to wind to an end this week as prosecutors and defense lawyers begin closing arguments.
The arguments will start at 11 a.m. ET on Monday and will last for roughly four hours. Senators will then have until Wednesday to make their final statements on the trial.
At 4 p.m. ET on Wednesday, the Republican-led Senate will vote on the two articles of impeachment against Trump. The chamber is widely expected to acquit the president, and last week, Senate Majority Leader Mitch McConnell called Trump to get his permission to push the final vote to this week.
Monday's proceedings come after the Senate blocked a motion to call new witnesses to testify in Trump's trial. Democrats had zeroed in on four witnesses they wanted to hear testimony from: John Bolton, the former national security adviser; Mick Mulvaney, the acting White House chief of staff; Robert Blair, an aide to Mulvaney; and Michael Duffey, an official in the Office of Management and Budget.
Bolton, in particular, claims of have firsthand knowledge of Trump's efforts to strongarm Ukraine into delivering politically motivated investigations targeting the president's rivals while withholding a $391 million military aid package and a White House meeting Ukrainian President Volodymyr Zelensky desperately sought and still has not gotten.
Mulvaney is the head of the Office of Management and Budget, which took on a lead role in carrying out Trump's order to freeze Ukraine's aid. Emails and other documents also indicate that Mulvaney was in the loop on Trump's decision to withhold Ukraine's military aid from the start.
Blair has direct knowledge of Mulvaney's involvement in the Ukraine pressure campaign.
And Duffey officially ordered the freeze in Ukraine's aid 91 minutes after Trump's phone call with Zelensky on July 25.
House impeachment managers, who act as prosecutors in Trump's trial, argued the Senate has a constitutional obligation to hear any relevant information pertaining to Trump's alleged misconduct.
The president's defense team, meanwhile, said the Senate didn't need to hear from any more witnesses while simultaneously claiming House prosecutors hadn't allowed for enough witnesses.
Watch the trial below:
Scroll down to follow Insider's live coverage of the trial:
A huge week in Washington politics
The Iowa caucuses, which officially kick off the 2020 primary season, are on Monday evening.
The four Democratic senators who are in the running for the party's nomination Bernie Sanders of Vermont, Elizabeth Warren of Massachusetts, Amy Klobuchar of Minnesota, and Michael Bennet of Colorado will have the chance to leave the chamber after closing arguments to head to Iowa.
On Tuesday night, Trump will deliver the State of the Union to Congress.
On Wednesday, the Senate will vote on whether to convict Trump and remove him from office. Two-thirds of the chamber, or 67 senators, need to vote to convict the president to trigger his removal, which is highly unlikely.
And on Friday, New Hampshire will host the eighth Democratic primary debate, which is shortly before the state's primary.