Schumer is demanding Senate Majority Leader Mitch McConnell, R-Ky., call Mulvaney, Bolton, Blair and Duffey as witnesses at Trump’s Senate trial. Emails made public last week showed that Duffey was the official who told the Pentagon that the president wanted the aid frozen — a request that came just hours after Trump’s July phone call with the Ukrainian president that has served as the backbone of the impeachment proceedings against him.

The four witnesses “were intimately involved” with what was going on behind the scenes, Schumer said.

“Let me be clear, this is about getting to the truth,” the Democratic leader said. “Will the Senate hold a fair trial or will it enable a cover-up? President Trump, if you are so confident you did nothing wrong, why won’t you let your men testify?”