What to expect this week as Pelosi prepares to send articles of impeachment

What's next: Once the articles are formally delivered to the Senate, the impeachment trial would begin almost immediately.

• The first few days of trial are expected to be procedural — including the swearing-in of Chief Justice John Roberts, U.S. senators as jurors and additional housekeeping items.
• Simultaneously, senators will debate the resolution laying out the terms for the trial, a Republican leadership aide told Axios. A vote on the resolution is expected to take place roughly three to four days after the trial begins, the aide said.

What they're saying: Pelosi told ABC's George Stephanopoulos this morning that "if we don't" see new witnesses or documents in the Senate trial "then it's a coverup."

• Pelosi defended her decision to delay the impeachment trial by several weeks in an attempt to force witnesses and document production, and she said the ball is now in Senate Majority Leader Mitch McConnell's court.
• She said McConnell will be held "accountable to the American people."
• Meanwhile, House Minority Leader Kevin McCarthy, appearing on Fox News' "Sunday Morning Futures," accused Pelosi of slow-walking impeachment to hurt Sen. Bernie Sanders' chances of winning the Democrats' Iowa caucuses by forcing him to be in Washington instead of campaigning.
• McCarthy's assertion is aimed at splitting Democratic voters, undercutting unity and prompting a faster trial.

Pelosi is poised to end the weeks-long impeachment standoff without two big commitments she has consistently pushed for:

1. A Senate resolution preemptively laying out the terms for the trial.
2. An agreement on document and witness requests at the outset of the trial. (McConnell successfully secured the necessary Republican votes to move ahead on setting the trial rules without negotiating with Democrats.)

The bottom line: Now the trial will begin on McConnell's terms.

As of now, the resolution is expected to broadly follow the contours of former President Bill Clinton’s 1999 trial.

• House managers and Trump's defense team will deliver opening statements, after which senators will submit their questions to the chief justice, launching a Q&A period.
• During this time, the Senate as a body will determine whether to call new witnesses, seek more documents and any other similar requests.

• The leadership aide estimated that this period will last at least two weeks.

Behind the scenes: Many Senate Republicans have said they think calling witnesses is a dangerous move that would unnecessarily drag out the trial, but a key GOP senator, Susan Collins of Maine, told reporters on Friday that she has been working with "a fairly small group" of GOP senators to ensure witnesses, such as Trump's former national security adviser John Bolton, are called.

• Collins, who is up for re-election this year, declined to say who or how many lawmakers she's been working with. Sen. Mitt Romney (R-Utah) has said he wants to hear from Bolton, particularly given Bolton's lawyer has said he has previously undisclosed information regarding the White House's dealings with Ukraine.
• Other moderate Republicans have dodged questions about potential witnesses, but if a handful decides to buck the party line, it could be enough.
• Republicans would need 51 votes to dismiss the case, and Democrats would need 51 votes to call witnesses. Republicans currently hold a 53-47 majority in the Senate.

Trump has remained committed to blocking any top administration officials, current and former, from testifying.

• In an interview with Fox News' Laura Ingraham that aired Friday, Trump said he'd likely invoke executive privilege if Bolton was subpoenaed.
• “I think you have to [invoke executive privilege] for the sake of the office,” Trump said.

Go deeper: Trump laments "stigma" of impeachment, suggests Senate shouldn't hold trial