Senate Majority Leader Mitch McConnell (R-Ky.) indicated in a closed-door meeting with Senate Republicans that he did not yet have enough votes to defeat an effort, expected later this week, to call additional witnesses and evidence in President Trump’s impeachment trial.

Pressure has ramped up to include witnesses after reports that former national security adviser John Bolton says in a book manuscript that Trump directly tied the holdup of nearly $400 million in military assistance to Ukraine to investigations of former vice president Joe Biden and his son Hunter Biden.

Trump’s defense team argued Tuesday that Democrats are seeking to remove him from office over policy differences as they offered their third and final day of opening arguments in a Senate trial on charges of abuse of power and obstruction of Congress.

The crux of the case for Trump’s impeachment is the allegation that he withheld military aid and a White House meeting with Ukrainian President Volodymyr Zelensky to pressure Ukraine to investigate the Bidens. Hunter Biden served on the board of Burisma, a Ukrainian energy company, while his father was vice president. Trump’s attorneys have argued that the president was justified in seeking investigations because of a history of corruption involving the company.

●White House works to contain damage from allegations in forthcoming Bolton book.

●Bolton book roils Washington as onetime allies turn on Trump’s former national security adviser.