Supreme Court Justice Clarence Thomas will administer the official constitutional oath to Judge Amy Coney Barrett on Monday night if she is confirmed by the Senate, a senior White House official told Fox News. 

Thomas has long been considered one of the more conservative justices on the Court, along with Barrett's mentor, the late Justice Antonin Scalia. The would-be celebration of her confirmation won't be a large affair, President Trump said, noting that it will be "just a very nice event."

Trump made those comments to reporters on Monday at Lehigh Valley International Airport in Pennsylvania, Politico reported. The president has been holding rallies in the swing state as part of a final push to win support for next week's election.

Barrett's confirmation, which is expected to take place on Monday evening, will mark his third successful appointment to the high court within his first term. The highly contentious process has provoked backlash from Democrats, who claim Republicans hypocritically jammed her nomination through after rejecting Judge Merrick Garland's in 2016. 

In a video retweeted by Senate Minority Leader Chuck Schumer, D-N.Y., he accused Republicans of committing "one of the greatest acts of hypocrisy that has ever occurred in the Senate."

ROMNEY PRAISES SUPREME COURT NOMINEE BARRETT'S 'INTEGRITY,' SLAMS 'DIVISION AND CONTEMPT FOR OTHERS' IN US

“This is something to be really proud of and feel good about,” Senate Majority Leader Mitch McConnell, R-Ky., said during a rare weekend session Sunday ahead of voting. He scoffed at the “apocalyptic” warnings from critics that the judicial branch was becoming mired in partisan politics, even as he declared that “they won’t be able to do much about this for a long time to come.”

Trump will also likely have to ward off criticism surrounding the ceremony he holds while the coronavirus continues to spread throughout the U.S. Like Barrett's nominating ceremony, Monday's would-be celebration will take place outdoors, although it's unclear whether attendees will refrain from wearing masks like they did during the former.

“We’re doing tonight the best we can to encourage as much social distancing as possible,” White House chief of staff Mark Meadows reportedly said of a potential swearing-in ceremony.

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Vice President Mike Pence, who also serves as president of the Senate, won't be presiding over the vote after members of his staff tested positive for the virus. Both he and his wife, Karen, have tested negative.

Schumer  and his leadership team said that Pence's attendance would not only violate virus guidelines of the Centers for Disease Control and Prevention, but “it would also be a violation of common decency and courtesy.”

The Associated Press contributed to this report.