"It’s so challenging to do those uncomfortable scenes," he says.

WASHINGTON — President Trump’s impeachment trial will now drag into next week — wreaking havoc on Monday’s Iowa caucus and bleeding into Tuesday’s State of the Union address, a White House source told The Post.

Friday was expected to mark the last day in the bitterly drawn-out partisan proceedings, but both House impeachment managers and White House counsel now want more time to make their closing arguments, the source said.

White House counsel is hoping proceedings will be done by Tuesday afternoon so Trump can make his State of the Union address having been acquitted by the Senate, the source said.

But the timing will come down to the wire, with the Secret Service needing to clear the Capitol Building around 3 p.m. in preparation for Trump’s arrival at the House of Representatives.

Senators on both sides — many facing tough re-election bids — also want to be able to make closing remarks to explain to their constituents their final vote, according to the source.

Each of the 100 senators is allotted approximately 15 minutes on each impeachment article under existing rules — an excruciating 50 hours — but it’s unlikely that will take place, the source said.

It’s understood Senate Majority Leader Mitch McConnell and Senate Minority Leader Chuck Schumer will be engaged in frantic horse-trading Friday as they try to create new outlines for the end of the trial.

The White House source said it was impossible to get through the end of the trial by Friday night, as originally planned.

The news of an extended trial was first reported Friday morning by Politico and the Washington Post, which published articles speculating that the trial could run until Wednesday.

GOP lawmakers and some Democrats appear desperate to cast their votes and get the trial — which has consisted of lengthy sessions in the Senate running into the dead of night — over and done with.

Republicans also wanted Trump to deliver his State of the Union having been acquitted by the Senate on the two impeachment articles, as is ultimately expected.

Sen. Lindsey Graham (R-SC) told a group of reporters Friday that he doubted the reports, saying he expected the trial to end “no later than tomorrow.”

“I would not put people in Gitmo through this until Wednesday. That would violate the Geneva Conventions,” Graham said, noting how arduous the proceedings have been.

But GOP Sen. Mike Braun of Indiana was less confident, telling reporters: “All I heard is that it is uncertain and it could be drawn out.”

An extended trial would also be dire for Democratic senators who are running for president, with Elizabeth Warren, Bernie Sanders and Amy Klobuchar all desperate to return to Iowa before the caucuses Monday.

It’s unclear if the Senate will sit on Saturday, but a prolonged trial would kill the trio’s plans to spend the days before the caucuses campaigning in Iowa — forcing them to stay in Washington as a winner is announced.

A similar motion was passed in the middle of President Bill Clinton’s 1999 impeachment trial — allowing time for closing arguments and public speeches from senators.