Video: Trump Impeachment Trial Day 7

Updated 1:22 p.m.

President Donald Trump's legal team argued forcefully against the relevance of testimony from former national security adviser John Bolton on Tuesday as the lawyers neared the end of their defense and the Senate braced for debate on whether to summon Bolton and other witnesses into the impeachment trial.

Attorney Jay Sekulow took a dismissive swipe at an unpublished book by Bolton that is said to contradict a key defense argument about Trump's dealings with Ukraine. Revelations about that book clouded White House hopes for a big finish Tuesday as well as a swift end to the impeachment trial, with Democrats demanding witnesses and some Republicans expressing openness.

"It is not a game of leaks and unsourced manuscripts," Sekulow said, calling the book "inadmissible" and not evidence.

Bolton's manuscript contains an account of an August conversation in which he says Trump told him that he wanted to withhold hundreds of millions of dollars in security aid from Ukraine until it helped him with investigations into political rival Joe Biden. It's a dramatic eyewitness rebuttal to claims by Trump and his legal team that the president didn’t hold up the aid for political reasons.

That assertion matters because Trump and his lawyers have repeatedly insisted that he never tied the suspension of security aid to political investigations.

While scoffing at the manuscript, Trump and the Republicans have strongly resisted summoning Bolton to testify in person about what he saw and heard as Trump's top national security adviser.

Hours of arguments on Monday from Trump's lawyers declared anew that no witness has testified to direct knowledge that Trump's delivery of aid was contingent on investigations into Democrats.

Bolton appears poised to say exactly that if summoned by the Senate.

Even as defense lawyers laid out their case as planned, it was clear Bolton's book had scrambled the debate over whether to seek witnesses. Trump's legal team has rejected the account, and Trump himself denied it.

“I NEVER told John Bolton that the aid to Ukraine was tied to investigations into Democrats, including the Bidens," Trump tweeted. "If John Bolton said this, it was only to sell a book.”

Read More: In Final Day Of Arguments, Trump Defense Focuses On Bar For Impeachment (via NPR.org)