(CNN)As Rear Adm. Ronny Jackson fights to salvage his nomination to head the Department of Veterans Affairs, Republicans in Congress are staying on the fence Wednesday, remaining unwilling to defend the White House physician but not yet ready to abandon him.
Congressional Republicans in uncertain spot over Ronny Jackson
"You don't just want to have somebody withdraw because there's an allegation. Nobody will ever get through this system," said Republican Sen. Lindsey Graham of South Carolina.
He added, "So the question is: Are they credible allegations? Give him a chance to tell his side of the story," he continued. "Let the committee determine, you know, how serious they are."
Graham, a close ally of Jackson's, was previously scheduled to introduce the rear admiral at his confirmation hearing that was set for Wednesday, but the Veterans Affairs Committee postponed it to further investigate allegations of professional misconduct, ranging from being drunk on the job to improper handling of prescriptions.
While the committee is looking into the claims, it has not substantiated them, with little documentation available to corroborate them. Jackson has given no signs that he plans to withdraw his nomination, telling reporters on Capitol Hill Tuesday that he can "absolutely" address the allegations. "I'm looking forward to rescheduling the hearing and answering everyone's questions.
President Donald Trump defended him at a news conference Tuesday as "one of the finest people I have ever met" and said it is "totally his decision" on whether Jackson wants to withdraw.
Georgia Republican Sen. Johnny Isakson, the chairman of the Veterans Affairs Committee, said Wednesday he still plans to hold a hearing for Jackson, though he didn't provide a sense of timing.
"The nominee deserves the chance to be heard. The President deserves a right for them to be heard. And the veterans deserve that we do our job," he told CNN. "We're going to give a good hearing, make the right decision, move forward, and we're going to do it in our schedule -- not on anybody else's."
But in the meantime, senators on both sides of the aisle want to dig deep on the claims. "My impression is that everyone is looking for the truth," said Sen. Jerry Moran, a Kansas Republican.
Sen. Mike Rounds, a GOP member of the committee, told CNN the sources of the information are "credible" but the allegations still need to be fully investigated.
"When you have these types of accusations or allegations that are being made by some individuals with a lot of credibility, then you want to follow them through," he said. "You want to find out what's going on."
The top Democrat on the committee, Sen. Jon Tester of Montana, said Wednesday on CNN that the committee is attempting to do just that, saying "we need to get to the bottom of these accusations to find out if they're true."
Republican lawmakers and aides have grown increasingly frustrated with the administration over the last several days -- something tied in part to the unconventional nomination itself and the lack of congressional consultation before it was made.
For days Republican aides described several senators who reached out to the White House for answers to the allegations -- only to receive little, if any, information about the veracity and severity of the situation or whether the White House was even aware of the extent of the claims, the aides said.
White House talking points defending Jackson only landed in Senate Republican inboxes Tuesday evening, multiple aides said. That has only served to further zap the willingness to go to bat for a nominee who was already lacking natural allies on the Hill.
"We're willing to keep our powder dry," one senior aide said, "But you aren't going to see many of our guys go out of their way to defend him until we get answers."
For the moment, GOP senators declining to attack Jackson or call for his nomination to be pulled is the best the administration can likely hope for, one senior GOP aide said. "We're all in wait-and-see mode right now," the aide said. "We'll see how long that lasts."
Echoing that sentiment, Sen. John Cornyn, the Senate's No. 2 Republican, said he and his colleagues want to hold off until they know more. "The first question is: What are the facts?" he said. "I hate the idea of people's lives being ruined by unsubstantiated allegations."
Republican Sen. Rand Paul said, at this point, it "sounds like gossip."
"I don't know yet what to believe and what not to believe," he said on Fox News. "It will take longer for me to understand that situation."
Underscoring the direness of the nomination is the concern Republicans already had about Jackson, given his lack of experience in management and public policy.
But in another sign of Republicans being hesitant to jump ship, Republican Sen. Jeff Flake -- Trump's most vocal GOP critic in the Senate -- was not ready to call for Jackson to drop out of the running.
"That's not my call," he told CNN. "But it seems to be a difficult road ahead -- definitely."