Now that the U.S. House of Representatives has impeached President Donald Trump, attention is now focusing on what comes next, specifically, in the U.S. Senate, where only the third impeachment trial in American history will be conducted.

Trump was impeached on two counts of high crimes and misdemeanors Wednesday night, becoming only the third sitting president in American history to be impeached, joining Andrew Johnson and Bill Clinton.

The two articles of impeachment passed by House Democrats — abuse of power and obstruction of Congress — point to Trump pressuring Ukraine to investigate 2020 political rival Joe Biden while withholding as leverage military aid the country relies to counter Russia as well as his efforts to block the House investigation.

RELATED: Georgia Democrats join colleagues in voting to impeach Trump

During a late-evening news conference after the House vote, Speaker Nancy Pelosi, whose Democrats led the impeachment charge, declined to say when she would send the articles over to the Senate, or even if she would.

Pelosi is reportedly concerned about whether Democratic charges against Trump would be given a fair hearing in Capitol Hill's other chamber, according to ABC News.

If Pelosi sends the articles over to the Senate, here are the major players who will decide the president’s fate:

Chief Justice John Roberts 

John Roberts will preside over Trump’s trial in the Senate. The chief justice of the Supreme Court is constitutionally obligated to preside over a sitting president’s impeachment trial. Roberts was appointed by then-President George W. Bush in 2005.

U.S. Sen. Mitch McConnell 

Mitch McConnell, a longtime senator from Kentucky, is the Senate majority leader in the Republican-controlled Senate. McConnell has already said he is not interested in calling Democrat-requested witnesses in a Trump impeachment trial, and Pelosi accused the majority leader Wednesday night of “being in cahoots” with the president’s lawyers.

In remarks prepared for a Thursday morning speech on the Senate floor, McConnell accused Pelosi of being afraid to send “their shoddy work product to the Senate.” He then described Trump’s impeachment as “the most rushed, least thorough, and most unfair impeachment inquiry in modern history.”

“The framers built the Senate to provide stability,” McConnell said. “To keep partisan passions from boiling over. Moments like this are why the U.S. Senate exists.”

U.S. Sen. Chuck Schumer 

The New York Democrat serves as Senate minority leader. Chuck Schumer has already said he will force votes on the Senate floor over witness testimony from White House chief of staff Mick Mulvaney, former national security adviser John Bolton and others.

That’s a long-shot request because McConnell and the GOP will not be forced into lengthening the impeachment trial of a sitting president in a White House election year.

Schumer went on the offensive Thursday morning, accusing McConnell of "hiding the truth" during a CBS appearance.

House impeachment managers

Pelosi said Wednesday night she “cannot name managers until we see what the process is on the Senate side, and I would hope that that will be soon. So far we haven't seen anything that looks fair to us, so hopefully it will be fairer, and when we see what that is, we'll send our managers.”

Whoever Pelosi appoints will manage the House’s impeachment articles through the Senate trial.

The president’s lawyers

The White House has not yet announced who would be Trump's lawyers in the impeachment trial. White House counsel Pat Cipollone is expected to play a leading role, an administration official told Reuters.