The urgent question of whether Bolton will be allowed to testify remains at the forefront. Democrats say the testimony will ensure a fair trial, while Republicans blame Democrats for not demanding Bolton's testimony earlier.
The vote to call witnesses is expected by Friday.
Wednesday's pointed, back-and-forth debate between House impeachment managers and the president's lawyers was driven by the written questions submitted by senators. Most were designed to emphasize political points. Democrats focused on the need for witnesses. Trump's defense team said his pressure on Ukraine for political help was normal foreign policy, not abuse of power.
Trump's defenders relied on retired professor Alan Dershowitz, a member of their team, who told senators that every politician conflates his own interest with the public interest. "It cannot be impeachable,” he declared Wednesday.
Read More: Impeachment Trial Q&A Enters Last Day Before Moving To Vote On Witnesses (via NPR.org)