Trump will deliver his speech just feet away from House Speaker Nancy Pelosi, looking out on a chamber full of senators who will serve as jurors in his trial.
The most vulnerable is Senator Doug Jones, who is up for re-election this year in Alabama. The impeachment proceedings will begin again at 4 p.m. ET Wednesday, when senators are set to take a formal vote on the articles of impeachment.
The president was impeached by the House of Representatives in December on charges of abuse of power and obstruction of Congress. He seemed temperamentally ill-suited for a power grab during the trial, although he has on occasion voted with the court's liberal wing and in 2018 rebuked Trump over the president's criticism of judges who have ruled against him.
Clinton was acquitted during a vote in the Senate a few weeks later, and Trump is expected to have the same fate at a vote scheduled for Wednesday.
House Republicans previous year attracted at least two Democrats to vote against the articles charging Trump with abuse of power and obstruction of Congress, though one later switched his party affiliation.
McConnell said the two impeachment charges against Trump - that he abused his power and obstructed Congress' ensuing investigation - are "constitutionally incoherent" and don't "even approach a case for the first presidential removal in American history".
Republican Senators Lamar Alexander, Marco Rubio and Rob Portman are among those who acknowledged the inappropriateness of Trump's actions, but said they would not vote to hear more testimony or to convict.
But Varney said despite the backlash from the Democrats, America stands tall.
The Senate seems certain to acquit Trump.
Any hints of fallout in the impeachment trial will be most closely watched in electoral districts and states closely divided between Republicans and Democrats and will play a pivotal role in November's House and Senate races.
But with the two parties immersed in election-year politicking, no major legislative action is expected this year.
Most Senate Democrats, like New Mexico's Martin Heinrich, said the evidence shows Trump is a danger to the country and must be removed from office. Democrats have accused Trump of withholding federal aid to Ukraine in order to start an investigation into his political opponent Joe Biden and his son, Hunter Biden.
Trump must also decide whether to use the speech to signal that he wants to work with Democrats to pass legislation in the coming months.
A senior administration official laying out plans for the speech wouldn't divulge whether the President would bring up impeachment during his remarks, but they did say the speech isn't being written "in a vacuum" and "it wouldn't be out of the ordinary for the speech to evolve before it's delivered".
The trial unfolded over almost two weeks and reached a decisive moment last Friday when senators voted against calling witnesses and documents.
The legislation argues that Trump "used the office of the president of the United States to attempt to compel a foreign nation to interfere with domestic political affairs for his own personal benefit" and says Trump "wrongfully enlisted his personal lawyer to investigate a domestic political rival by meddling in formal diplomatic relations in a manner that is inconsistent with our established National Security Strategy". About a dozen senators delivered speeches on Monday evening, with no signs of partisan defections.
"Is there one among you who will say: "Enough"?" asked Rep. Adam B. Schiff, telling GOP senators that even a single vote for conviction from one of them would make an important statement.
Speaking ahead of Murkowski, he acknowledged the pressures of being a "moderate centrist Democrat" in a pro-Trump state, while speaking favorably about the arguments made by the House impeachment managers and Trump's defense team.