The request was made in a letter from House impeachment managers, which suggests they intend to present "an aggressive case," for which they have charged Trump with inciting a mob of supporters who stormed the Capitol on Jan. 6 (through an open door).

In the letter, Rep Jamie Raskin, one of the impeachment managers, asked that Trump provide testimony "either before or during the Senate impeachment trial," and under cross examination, about his conduct on Jan. 6, as early as Monday and not later than next Thursday, Feb. 11.

Raskin said that Trump questioned critical facts in the case "notwithstanding the clear and overwhelming evidence of your constitutional offense."

"In light of your disputing these factual allegations, I write to invite you to provide testimony under oath, either before or during the Senate impeachment trial, concerning your conduct on January 6, 2021," Raskin wrote. -Associated Press

If Trump refuses to testify, they will use it against him in trial, according to Raskin, who noted that former presidents Gerald Ford and Bill Clinton provided testimony while in office, and that the Supreme Court has held that Trump is not immune from the legal process. 

"If you decline this invitation, we reserve any and all rights, including the right to establish at trial that your refusal to testify supports a strong adverse inference regarding your actions (and inaction)," Raskin concluded.

Trump spox Jason Miller, meanwhile, doesn't expect Trump to testify, but that if he did, the former President would 'knock this thing out in about 15 minutes.'