Senate Majority Whip John Thune, R-S.D., said Tuesday that Democrats are learning the same lesson the GOP did in 1999: Impeachment proceedings can actually be a boon to the sitting president.

Thune, who was the state's lone congressman during President Clinton's impeachment, said House Speaker Nancy Pelosi, D-Calif., likely knew an impeachment inquiry could hurt her party going forward but was "pushed into" starting one by far-left members of the Democratic Party.

REPUBLICAN SUSAN COLLINS ANNOUNCES SHE WILL VOTE TO ACQUIT TRUMP

"And I think the American people are paying the price for that," Thune added. "But honestly, the president politically -- and I think Republicans politically -- are finding out the same thing we found out in 1999 with Bill Clinton -- that his numbers went up and ours went down. And I think the president’s numbers are going up, and I think the Democrats numbers are going down."

Regarding Wednesday's final vote to convict or acquit President Trump on the two impeachment articles, Thune told host Bill Hemmer that there is only a "small universe" of Democrats who could side with the GOP.

"I think that there are some of them are going to be in a very tough spot if they vote to convict the president in the kind of states that they represent," he said. "I think that there are perhaps a few that are gettable. We will see. We will not know until tomorrow."

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Political observers have cited Sens. Joe Manchin of West Virginia, Kyrsten Sinema of Arizona and Doug Jones of Alabama as Democrats who could vote to acquit the president.

Shortly after Thune spoke to Hemmer, Sen. Susan Collins, R-Maine, announced she would vote to acquit Trump on both articles of impeachment. Sen. Mitt Romney, R-Utah, is the only GOP member whose vote is in play.