"There is no defensible reason to wait until his book is published, when the information he has to offer is critical to the most important decision Senators must now make — whether to convict the President of impeachable offenses," they continued.

The Times report comes as a curveball in the middle of Trump's impeachment trial, which could wrap as soon as this week.

Trump's legal team began presenting its defense on Saturday, including arguing that the president's decision to hold up Ukraine aid was tied to concerns about corruption or a belief that Europe wasn't doing enough to support Ukraine.

The push for Bolton's testimony comes as the Senate could vote as soon as midweek on whether to allow new witnesses or documents. In addition to Bolton, Democrats want to hear from acting chief of staff Mick Mulvaney, Mulvaney's adviser Robert Blair and Michael Duffey, an Office of Management and Budget staffer.

"Senators should insist that Mr. Bolton be called as a witness, and provide his notes and other relevant documents. The Senate trial must seek the full truth and Mr. Bolton has vital information to provide," the House managers said."Bolton is screaming 'call me as a witness.' Willful blindness to the truth is a gross violation of their constitutional duty, especially when a big part of Trump’s defense is that he didn’t withhold Ukraine aid for personal political favors," he said.