WASHINGTON, D.C. - U.S. Sen. Pat Toomey says he is not advocating for more witnesses in President Donald Trump’s impeachment trial. But, if the Senate approves to hear from them, he believes both the prosecution and defense should each get to call someone to the stand.

During a one-on-one interview with Erie News Now on Wednesday, Toomey said he has not advocated nor will he advocate for a so-called ‘one-for-one’ witness trade-off during the trial. According to a Washington Post report Monday, Toomey was discussing the possibility with GOP colleagues.

For now, Toomey, a Republican and junior senator from Pennsylvania, said he is not in favor of additional witnesses despite increasing demand from some senators within his own party to hear from former National Security Advisor John Bolton.

“I am suggesting that it would be unacceptable to bring in Bolton without giving the defense an opportunity,” Toomey said.

Bolton is ‘extremely unlikely’ to have any new information that is going to change the nature of the allegations against Trump, according to Toomey. But the timing of a one-for-one swap comes when Senate Majority Leader Mitch McConnell may no longer have the vote to prevent further witness testimony. Although Toomey isn’t advocating for that option, he hasn’t totally ruled it out, either.

“I’m not at all convinced that the combination of one-and-one is desirable at all,” he said. “I’ll wait to make a final decision on that.”

If more witnesses are called, Toomey and the bulk of Senate Republicans want to hear from Hunter Biden, the son of former vice president Joe Biden. Hunter Biden worked for a Ukrainian energy company while his father was in office.

Trump is charged with abuse of power and obstruction of Congress. At the center of both charges: Democrats say the president tried to leverage nearly $400 million in U.S. military aid to Ukraine in exchange for an investigation of his political rivals, notably the Bidens. The alleged quid pro quo was offered during a phone call between Trump and Ukrainian President Volodymyr Zelensky on July 25. The President was impeached by the U.S. House in December.

In addition to witnesses, senators may demand to see more evidence to further their decision on whether or not to remove Trump from office.

New York Sen. Kirsten Gillibrand was among the Democratic presidential hopefuls who called for impeachment hearings against Trump after the report from Special Counsel Robert Mueller when Mueller testified before Congress last summer. Now, however, she’s focused on the evidence at hand.

“It’s not necessary,” Gillibrand said of the Mueller Report in the trial. “These allegations of soliciting a bribe from the Ukrainian leader in exchange for a political rival is equally as serious and equally as damning. So, I will look at the evidence presented by the House specifically in these two articles for impeachment.”

Senators are expected to continue asking questions of both House Managers and Trump’s legal counsel throughout the day Thursday. A vote on witnesses has not been scheduled, but is expected as soon as Friday.