“Sources close to Senate Majority Leader Mitch McConnell tell Axios that, if it appears that at least 51 senators will vote for witnesses, McConnell and Schumer will likely try to hash out an agreement rather than going straight to a vote.”

“If the Senate goes that route, Republicans are likely to demand their own list of witnesses — with Joe Biden’s son Hunter at the top.”

“This has privately created a dilemma for some Democrats, who are eager for more information but recognize that a vote for witnesses could open the door for Republicans to use the impeachment stage to try to deal an insurmountable blow to the campaign of a rival thought to pose the greatest risk to Trump in the general election.”

“President Trump’s team of lawyers did not change their tactics Monday despite bombshell new revelations related to former national security adviser John Bolton’s alleged knowledge about the Ukraine affair at the center of the president’s impeachment trial,” The Hill reports.

“In hours of arguments on the Senate floor, Trump’s attorneys did not address or seek to knock down Bolton’s account, as Trump himself has done.”

Sen. Patrick Toomey (R-PA), an influential conservative in the Senate, has spoken with several colleagues in recent days about possibly summoning just two witnesses to President Trump’s impeachment trial, with one called by Republicans and one by Democrats, the Washington Post reports.

“Toomey has confided to GOP senators that proposing a ‘one-for-one’ deal with Senate Democrats may be necessary at some point, particularly with pressure mounting for witnesses to be called… He has argued that such an arrangement could force Democrats to accept a Republican witness against their wishes or else risk having Republicans move ahead to acquit Trump.”

“The defense team’s strategy rests on pretending that news doesn’t exist.”

— Rep. Justin Amash (I-MI), observing that President Trump’s lawyers are ignoring reports about John Bolton’s book in their impeachment defense.

“Senate Republicans were thrown off-balance Monday by the latest John Bolton revelations, offering a range of convoluted — and at times contradictory — responses to an episode that threatens to upend President Trump’s impeachment trial,” Politico reports.

“GOP senators, who hadn’t yet had time to coordinate their responses before arriving at the Capitol, offered an all-over-the-map assessment of the significance of the former national security adviser’s claim that Trump told him he would continue withholding military aid until Ukraine provided information about investigations he had been seeking into his Democratic rivals, including former Vice President Joe Biden.”

Sen. Angus King (I-ME) told NPR that as many as 10 Republican senators would eventually vote in favor of allowing new witnesses during President Trump’s impeachment trial.