He then went to say that Mitch McConnell doesn't want any witnesses and it seemed like Republicans were about to follow suit. Neither Bolton nor a spokesman for the publisher, Simon & Schuster, responded to a request for comment.
At the beginning of the trial, the Senate decided it would vote on additional evidence after lawmakers completed their 16 hours of written questions for both President Trump's attorneys and the House managers prosecuting the case.
At only the third-ever presidential impeachment trial in U.S. history, Trump's lawyers closed out their three-day defence in the Senate by calling for a speedy acquittal of Trump and accusing Democrats of bringing politically motivated charges in an attempt to reverse his 2016 election victory.
Republican Senator Tom Cotton on behalf of himself and Republican Senators John Boozman, Martha McSally, Marsha Blackburn, John Kennedy, and Pat Toomey to the president's counsel: "Did the House bother to seek testimony or litigate executive privilege issues during the month during which it held up the impeachment articles before sending them to the Senate?"
Removing Trump from office would take a two-thirds majority. There are 53 Republican senators and none of them has publicly advocated removal.
Trump denied the claim attributed to Bolton.
In a pair of tweets, Trump said he named Bolton as his top security aide even though others told him "don't do it, sir", and fired Bolton because "if I listened to him, we would be in World War Six by now".
National Security Advisor John Bolton unveils the Trump Administration Africa Strategy at the Heritage Foundation in Washington on December 13, 2018. "Who would do this?"
Bolton's allegations go to the heart of impeachment charges against Trump.
Trump faces charges from Democrats that he abused his power like no other president, jeopardizing U.S. -Ukraine relations by using the military aid as leverage while the vulnerable ally battled Russian Federation. Biden has been leading most polls in the upcoming Democratic primary, and polls recently conducted by ABC News as well as Fox News indicate Biden is the Democrats' best candidate to defeat Trump in November.
Rep. Eliot Engel pushed back on President Donald Trump's claims that John Bolton didn't complain about the president's conduct toward Ukraine as the Foreign Affairs Committee chairman revealed a September call with Bolton in which the former NSA chief told him to examine the ouster of the former US ambassador to Ukraine.
For much of the last 20 years, John Bolton was a conservative poster child, a Republican hawk whose worldview helped shape the GOP establishment's approach to dicey foreign policy questions.
"I've said from the beginning that I felt that it was likely that we would need to call a couple of witnesses... in order to clarify some ambiguities, answer some questions".
Among those who be watching the session Wednesday is Joseph Bondy, the attorney for Lev Parnas, the former associate of Rudy Giuliani. He was trailed by TV cameras, photographers and sign-toting demonstrators.
The trial picks up again at 1 p.m. Wednesday. Bolton has also said that he is willing to testify if he is subpoenaed in the impeachment trial. Parnas, facing federal campaign finance charges in NY relating to donations to a pro-Trump political group and others, has provided information to House Democrats damaging to Trump.
Parnas indicated willingness to testify in the trial, adding, "The president knew everything that was going on with Ukraine".
Murkowski has appeared open to the idea of witnesses.
Democrats are demanding Mr Bolton testify in the wake of these claims, and some Republicans have also suggested they would like to hear from the former adviser.
© Drew Angerer/Getty Images Defense team member and U.S. President Donald Trump's personal lawyer Jay Sekulow speaks to reporters during a recess in the impeachment trial at the U.S. Capitol on January 22, 2020 in Washington, DC.