Democrats say they are holding out hope that they will win over enough Republicans to convict the former president for his role in the Jan. 6 Capitol riots, in which five people died.
"There will be a trial," Senate Majority Leader Chuck Schumer said in making the announcement Friday. "It will be a full trial, it will be a fair trial."
The Democrats, all of whom are lawyers and many of whom have deep experience investigating the president, face the arduous task of convincing skeptical Senate Republicans to convict Trump.
Three House Democrats are planning to introduce articles of impeachment against President Donald Trump on Monday, meaning the chamber could potentially vote on his removal from office by midweek, according two people familiar with the planning.
Trump called Michael Atkinson a "disgrace" after informing Congress late Friday night that he intended to fire him. In letters to the House and Senate intelligence committees, Trump wrote that he had lost confidence in Atkinson but gave little detail.
President Trump on Friday abruptly fired the inspector general of the intelligence community, sidelining an independent watchdog who played a pivotal role in his impeachment even as his White House struggled with the deepening coronavirus pandemic.
Trump's efforts to have Ukraine investigate the Bidens were central to the impeachment charges he faced. Romney was the only Republican who voted to convict.
Democrats have demanded more information about Barr's intervention in the case of Roger Stone, a longtime Trump confidant who was convicted in November of lying to Congress and other charges.
"In a way I do feel like I'm introducing myself to a number of the senators," Schiff said in an interview with The Associated Press before arguments resumed on Thursday.