Even vulnerable Republicans, such as Cory Gardner of Colorado, who faces a competitive reelection race in 2020, expressed no interest in hearing from Bolton.

“Is Nancy going to send the articles over? She doesn’t seem to care?” said Gardner, referring to Speaker Nancy Pelosi. "You guys want to have a trial by Twitter but until she has the articles sent over there is no trial.”

Meanwhile, Trump’s allies are losing patience with Pelosi and are accusing her of trying to dictate the terms of the Senate trial by withholding the articles of impeachment. Sen. Lindsey Graham (R-S.C.), a staunch Trump ally, reiterated Monday he would move to change Senate rules to allow the chamber to move forward on its own authority if Pelosi refuses to transmit the articles soon.

“From my view, I think we should urge the speaker to send over the articles [of impeachment]. If she doesn’t, we should change the rules,” Graham told reporters on Monday. “You can’t let her use the rules against us. She has a duty to transmit them.”

“I don’t want to turn the Senate over to Nancy Pelosi,” Graham added.

Sen. Josh Hawley (R-Mo.) also introduced his own resolution Monday that would allow the Senate to dismiss the articles of impeachment “for lack of prosecution.”

"My view is that the majority leader's made a very generous offer to Democrats, which is: Let's use the Clinton rules and start this trial. And we can decide witnesses and so forth later,” Hawley said. “Now, I don't know why we would call witnesses on the Democrat side. They've had their chance."

Hawley and other Republicans have argued that they should rely on the same information the House used to impeach the president. In their view, if the House could impeach Trump based on the information presented to the chamber, the Senate can make its decisions based on the same evidence.

The House voted in December to impeach Trump on charges of abuse of power and obstruction of Congress, after he pressured the Ukrainian government to investigate his political rivals in exchange for military aid.

McConnell and Senate Minority Leader Chuck Schumer sparred again about the terms of the Senate impeachment trial on the floor Monday. McConnell is insisting the Senate use the same format as President Bill Clinton’s 1999 impeachment trial, when the Senate decided unanimously to initially hear arguments and then call witnesses.

“The Senate has a unanimous bipartisan precedent for when to handle midtrial questions such as witnesses: In the middle of the trial,” McConnell said Monday. “The Senate said, 100 to nothing, that was good enough for President Clinton. So it ought to be good enough for President Trump. Fair is fair.”

But Schumer has rejected that argument, noting the Clinton impeachment trial had sworn testimony from witnesses.

“Leader McConnell’s view of the trial is an Alice-in-Wonderland view,” Schumer said. “When Leader McConnell proposes that we follow the 1999 precedent, he is essentially arguing that we should conduct the entire impeachment trial first, and then once it’s over, decide on whether we need witnesses and documents.”

Andrew Desiderio, Burgess Everett and Sarah Ferris contributed to this report.

