Here are some key questions to help Americans understand what the results of the impeachment trial could mean for the president and the country.
Why is the Senate holding an impeachment trial? When will it finally vote on articles of impeachment?
Right now, the Senate is in the middle of a trial, which is mandatory for all impeachments under the Constitution.
Supreme Court Chief Justice John Roberts, who is presiding over the trial, swore in the 100 senators who promised to "do impartial justice according to the Constitution and laws."
The senators have been acting like a jury in typical courtroom proceedings. First, House managers presented their case, then Trump's defense team would have equal time to rebut the charges.
Senators also vote on rules of the trial, like whether or not the House managers can take witnesses.
After all of this, the Senate deliberates.
Once a decision has been reached, the Senate meets in open session to vote on each article of impeachment. Senators will stand one by one at their desks and offer their verdict, guilty or not guilty.
It takes a vote of two-thirds of those present (67 out of 100 if everyone is there) to convict and remove the president from office.
The timing of this final vote remains uncertain, although it appears a Wednesday vote will bring the impeachment trial to an end.
Will Trump be convicted and removed from office?
Trump is most likely to be acquitted, meaning he would not be removed from office and can continue to govern as usual.
The Senate is Republican-controlled, with 53 seats, and no GOP senator has indicated that they would vote against Trump.
Some Republicans, like Sen. Lamar Alexander of Tennessee, said they believe the president abused his power but do not think his actions rose to the impeachable level.
What happens if Trump is acquitted?
If acquitted, President Trump can continue to govern as usual.
While Trump is the third president to be impeached, and Nixon resigned before his likely impeachment, an acquittal would mean no president in the history of the United States would be removed from office through impeachment.
Still, Speaker Nancy Pelosi has hinted that the House could take further action against Trump if the Senate acquits, ABC News has reported.
Pelosi was asked whether the House would attempt to compel former National Security Adviser John Bolton to testify in the lower chamber should the Senate trial end without his testimony.
"We'll see what happens," she said.
This impeachment trial comes during an election year as Trump is hoping to secure a second term.
In response, the president has cast himself as a victim.
"We have great Republicans out there and they don't like it any better than you do," he said of impeachment at a plant in Michigan. "A very partisan situation."
Despite rumors spread on Facebook, an acquittal would not grant Trump the ability run for office two more times. No person can be elected president three or more times: This is clearly stated in the Constitution.
What happens if Trump is convicted?
In the unlikely case that the Senate convicts President Trump, the country would enter an unprecedented situation. Trump would be automatically removed from office, and Vice President Mike Pence would become president.
It's not clear how quickly the succession would happen, but the Constitution does not contemplate any gap between a Senate vote to convict and the new president assuming power.
The Constitution does not prevent a president from running for election after an impeachment conviction, and conviction is not an automatic disqualification from holding office.
Why was Trump impeached in the first place?
Trump was impeached by the House last month on two charges, first that he abused his power like no other president, jeopardizing U.S.-Ukraine relations.
The charges against Trump, or articles of impeachment, are related to his July phone call to the president of Ukraine, who he asked to investigate his 2020 political rival Joe Biden. Democrats said Trump withheld U.S. military aid in a quid pro quo in exchange for this information.
The second article of impeachment says Trump then obstructed the House probe in a way that threatened the nation's three-branch system of checks and balances.
The Associated Press contributed to this report.