• The Senate will vote Friday evening on whether to call witnesses to testify in President Donald Trump’s impeachment trial.
  • But the prospect of witnesses being called seems as good as dead.
  • The motion to call witnesses requires a simple majority in the Republican-controlled Senate, requiring at least four GOP senators to vote with the Democrats.
  • The motion passing or failing rests on the shoulders of Sen. Lisa Murkowski, who has yet to reveal her vote, as well as Chief Justice John Roberts, who could break a tie.
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The Senate is set to vote Friday whether to call witnesses to testify in President Donald Trump’s impeachment trial, but as of Thursday night the attempt to subpoena documents and witnesses looked all but dead.

The motion to call witnesses requires a simple majority in the Republican-controlled Senate, requiring at least four GOP senators to vote with the Democrats. Just four Republican senators have appeared open to such a motion: Sens. Susan Collins of Maine, Lisa Murkowski of Alaska, Mitt Romney of Utah, and Lamar Alexander of Tennessee.

Collins announced late Thursday she would vote yes to the motion to call witnesses, and while Romney has not officially declared how he will vote, he expressed support during the impeachment process for calling witnesses.

Alexander, however, has announced he will vote no on the motion. “The Constitution does not give the Senate the power to remove the president from office and ban him from this year’s ballot simply for actions that are inappropriate,” he said on Twitter.

"Let the people decide," he concluded, referring to the 2020 presidential election.

Murkowski said she would announce her vote Friday.

If Murkowski, Collins, and Romney vote yes along with all Democrats, the vote would be 50-50, thus placing the onus upon Chief Justice John Roberts to break the tie. The motion will fail if Roberts, who is presiding over the trial, abstains from voting.

If the motion fails to call witnesses to the trial, the Senate will move on to vote on each article of impeachment. It requires a two-thirds majority to remove a president.

Trump was impeached by the Democrat-controlled House in December on charges of abuse of power and obstruction of Congress. His impeachment trial began January 21, with the Senate deliberating the rules of the trial.

Both the House impeachment managers and Trump's defense team had 24 hours over multiple days to present their arguments, and senators had 16 hours to ask questions.

The main witnesses Democrats want to call are the former national security adviser John Bolton and the acting White House chief of staff, Mick Mulvaney. Republicans have said that if witnesses are called, they would seek to call former Vice President Joe Biden and his son Hunter.

House Democrats made the case that Trump solicited foreign interference in this year's election and damaged national security by holding up nearly $400 million in congressionally mandated military aid to Ukraine and a White House visit sought by the country's president to pressure Ukraine into announcing investigations into Trump's political rivals, including the Bidens.

In his Twitter thread explaining his decision not to support calling witnesses, Alexander said that Democrats had proved their case but that Trump's actions did not warrant removal from office by the Senate.