President Donald Trump's fellow Republicans in the US Senate have come under renewed pressure to allow witnesses in his impeachment trial, while his defence team largely ignored disclosures from former White House national security advisor John Bolton.
The elephant in the room on the second day of Mr Trump's defence arguments was Mr Bolton whose unpublished book manuscript, according to the New York Times, included disclosures that go to the heart of the abuse of power charge against Mr Trump.
Mr Bolton wrote that Mr Trump told him he wanted to freeze $391 million in security aid to Ukraine until Kiev helped with investigations into Democrats, including political rival Joe Biden, and his son Hunter Biden, the Times reported.
The Bolton disclosures prompted new calls by Democrats for Mr Bolton and other witnesses to testify.
Democrats said Mr Trump used the aid to a vulnerable ally facing Russian aggression as leverage to get a foreign country to help him smear a domestic political rival.
Republican Senator Mitt Romney, a moderate who has at times criticised Mr Trump, said there was a growing likelihood that at least four Republican senators would choose to call Mr Bolton to testify, which would give Democrats the votes necessary in the Republican-led Senate to summon him.
Senator Ted Cruz, a staunch defender of Mr Trump, said the Bolton book would not "impact the legal issue before this Senate".
Mr Trump denied telling Mr Bolton that he sought to use the aid to pressure Ukrainian President Volodymyr Zelenskiy to investigate the Bidens on unsubstantiated corruption allegations.
"I haven't seen the manuscript, but I can tell you nothing was ever said to John Bolton," Mr Trump told reporters.
High-profile lawyers pick up the Trump case
In the Senate, Mr Trump's legal team resumed its presentation of opening arguments in the trial, including remarks by Ken Starr, the former independent counsel whose investigation into a sex scandal led to the 1998 impeachment of President Bill Clinton, a Democrat.
Defence lawyers turned to Joe Biden, one of the President's leading Democratic rivals as he seeks re-election in November, and Hunter Biden, who sat on the board of Ukrainian energy company Burisma while his father was US vice-president.
Pam Bondi defended Mr Trump's use of unsupported corruption allegations against the Bidens as the basis for his demand that Ukraine investigate them.
"All we are saying is that there was a basis to talk about this, to raise this issue, and that is enough," Ms Bondi said.
Ukrainian officials have said they found no indication that Hunter Biden had broken any law. Biden campaign spokesman Andrew Bates dismissed Ms Bondi's allegations, saying they had been widely discredited.
"The president's lawyers spent about two hours trashing the Bidens," said Representative Adam Schiff, the lead House impeachment prosecutor.
Another Clinton impeachment alumnus, Alan Dershowitz, carried a pair of worn antique books as he began closing the day's defence with an argument disputed by most legal scholars.
"Purely non-criminal conduct, including abuse of power and obstruction of Congress, are outside the range of impeachable offences," he said.
Mr Dershowitz himself argued the opposite view during Mr Clinton's impeachment.
Mr Trump's team closed the day by saying they would be back for the final day of their opening argument on Wednesday.
ABC/Reuters
