Washington (CNN) Former national security adviser John Bolton has remained silent in the immediate aftermath of President Donald Trump's Senate impeachment acquittal, an outcome many Democrats have cast as the result of a "sham" trial due, in part, to the fact that they were denied a chance to hear the former top aide testify.

Through his legal team Bolton suggested at various points throughout the impeachment process that he had new information relevant to the probe. Portions of his unpublished book manuscript, made public in the days prior to the Senate vote on witnesses, offered glimpses of what he may have told lawmakers under oath if given the chance.

According to a draft manuscript of the book obtained by The New York Times , Bolton writes that Trump ordered him to help with the pressure campaign to push Ukraine to dig up dirt on Trump's Democratic rivals.

But Bolton, who is seeking to remain a player in the Republican foreign policy space, according to those familiar with his future plans, has avoided becoming a star witness.

He refused to testify before the Democrat-controlled House inquiry, saying the White House hadn't authorized him to appear. He then said that if subpoenaed, he would come before the Republican-controlled Senate, which voted against hearing from witnesses.

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