Here's how the schedule for Trump's upcoming Senate impeachment trial could unfold

At Tuesday's Democratic caucus meeting, House Democrats are set to plan votes on resolutions to transmit the articles of impeachment to the US Senate and appoint impeachment managers this week.
Playbook anticipates that the Senate will take around three to four days of "housekeeping" to set the rules and procedures for the trial before issuing a summons for Trump to enter a plea and appear.
The exact timing and schedule of the trial will highly depend on whether the Senate calls key witnesses to testify, or if they hear no additional testimony and vote after hearing arguments from both sides.
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On the week of January 13, House Speaker Nancy Pelosi is expected to finally transmit two articles of impeachment charging President Donald Trump with abusing his office and obstructing Congress to the US Senate.

Next, the Senate will hold a trial determining whether to convict Trump on those charges, which would result in Trump's removal from office. Both sides will present their cases to the senators, who act as jurors, while Chief Justice John Roberts will preside over the hearings.

For several weeks after the House voted to impeach Trump, Pelosi withheld the impeachment articles from the Senate amid a standoff with Sen. Majority Leader Mitch McConnell over the trial's rules, and whether the Senate would call additional witnesses to give the jurors the most information possible.

The exact timing and schedule of the trial will highly depend on whether on the Senate calls key witnesses who defied House subpoenas, including former National Security Adviser John Bolton who has said he will comply with a Senate subpoena for this testimony and acting chief of staff Mick Mulvaney.

The Senate requires a majority vote to approve subpoenas, meaning at least three Republican votes would be needed to call witnesses. GOP Sen. Susan Collins said that she supports calling witnesses , and is trying to rally the Republican votes necessary to subpoena further testimony beyond that presented in the House's impeachment hearings.

On Monday morning, Politico's daily Playbook newsletter shed some more light on the schedule and timing of how Trump's impeachment trial could play out over the next few weeks:

At Tuesday's Democratic caucus meeting, House Democrats are set to plan votes on resolutions to transmit the articles of impeachment to the US Senate.
On Tuesday or Wednesday, they are also expected to vote to appoint impeachment managers, Democratic representatives who will act as prosecutors in making the case for convicting Trump to the US Senate.
Playbook anticipates that the Senate will take around three to four days of "housekeeping" to set the rules and procedures for the trial before issuing a summons for Trump to enter a plea, and appear to argue his defense.
The length and schedule of the trial will depend on how many witnesses if any are called to testify, but McConnell has indicated he will keep the Senate in session six days a week to ensure a speedy trial. (Bill Clinton's impeachment trial in January of 1999 lasted for five weeks).
The New York Times has reported that White House counsel Pat Cipollone and Jay Sekulow, one of Trump's personal attorneys, are expected to lead the strategy of Trump's defense in the Senate.

The timing of the impeachment trial will also likely come into conflict with the first primary contests of the 2020 presidential race, causing headaches for Democrats.

Democratic Senators running for president including Sens. Bernie Sanders , Elizabeth Warren , and Amy Klobuchar could be stuck in Washington in the crucial weeks and days before the Iowa caucus and New Hampshire primary.

For Trump to be convicted, two-thirds of the Senate 67 members must vote to convict him. The Senate consists of 53 Republicans, 45 Democrats, and two independents who caucus with Democrats, meaning Trump is highly unlikely to be removed from office.

Congress has never removed a president through the mechanism of impeachment. While two US presidents Andrew Johnson and Bill Clinton were previously impeached by the House, both were acquitted in the Senate .

Trump's efforts to solicit Ukraine's interference in the 2020 election while withholding a nearly $400 million military-aid package to the country, which is at war with Russia will be at the center of the impeachment trial. Trump also refused to grant a White House meeting to Ukrainian President Volodymyr Zelensky.

The catalyst for the inquiry was a whistleblower complaint detailing a July 25 phone call during which Trump repeatedly pressured Zelensky to announce investigations into former Vice President Joe Biden and his son Hunter, who served for five years on the board of Burisma Holdings, a Ukrainian oil-and-gas company .

Multiple career diplomats and national-security officials testified that the Trump administration explicitly conditioned a lifting of the military-aid hold and a White House meeting on Zelensky publicly announcing investigations into Burisma and a discredited conspiracy theory that Ukraine meddled in the 2016 US election.