President Trump’s plan to put ally Stephen Moore on the Federal Reserve Board appeared on the edge of failure Tuesday after one Republican senator said she was “very unlikely” to vote for Moore and several others sharply criticized him.

Sen. Joni Ernst (R-Iowa) became the first senator to go on record as a likely “no” vote.

“Stephen Moore, I am going to make a comment on that,” Ernst said, interrupting a trip to the Senate floor to return to address a reporter after Moore’s name was mentioned. “Very unlikely that I would support that person.”

Ernst, who said she had shared her views with the White House, said she “didn’t think” Moore would be confirmed if Trump follows through on his plan to nominate the former campaign adviser, adding that “several” senators agree with her on Moore.

Her assessment was affirmed by Sen. Tim Scott (R-S.C.), who said Moore’s best hope was to barely squeak by.

“I think he’s probably down to the high water mark now of 50 or 51,” said Scott, who declined to say how he would vote and said he wanted to review Moore’s record as a whole.

Beyond Ernst, three other female Republican senators — Susan Collins (Maine), Marsha Blackburn (Tenn.) and Shelley Moore Capito (W.Va.) — expressed serious concerns about Moore. They cited his comments saying there would be societal problems if men were not the breadwinners in the family, denouncing co-ed sports and saying female athletes do “inferior work” to men.

If four of the 53 Republican senators reject Moore, his nomination would probably fail, as no Democrats are expected to back him. The White House has yet to formally nominate him, raising the possibility that Moore’s nomination could be finished before it ever officially begins.

“It’s hard to look past some of those [comments]," Moore Capito said.

Blackburn said she has known Moore for a long time but was troubled by what he said as recently as 2014, when he wrote a column questioning whether it would cause societal unrest if women earned more than men.

“Of course his comments are something that are not good and you can guarantee — be guaranteed, absolutely without fail — if I visit with him that would be a topic of discussion,” Blackburn said.

Sen. Lindsey O. Graham (R-S.C.), a close friend of Trump’s, expressed concerns of his own.

“It will be a very problematic nomination,” Graham said Tuesday, although he said he is “still looking” at Moore and hasn’t made up his mind on whether to support him.

Trump keeps saying the economy would be even stronger — with higher growth and a higher stock market — if the Fed had not raised interest rates so many times last year. He has been on a quest in 2019 to fill the remaining two spots on the Fed’s board with people who are loyal to him and believe interest rates should be reduced.

Trump’s other intended nominee — businessman Herman Cain — withdrew from consideration after four GOP senators signaled they would not vote for him.

Sen. Lisa Murkowski (R-Alaska), who said publicly she would not vote for Cain, said Tuesday she had a view on Moore but declined to make it public. “I’m going to share it with the White House,” she said.

Collins, another GOP swing vote, said she wasn’t just concerned about Moore’s comments on women but also whether he would maintain the Fed’s independence from politics.

“Obviously some of his past writings are of concern. I feel strongly about the independence of the Federal Reserve. I would also want to explore that issue with him,” Collins said. “It certainly appears that he has a lot of personal financial issues as well as troubling writings about women and our role in society, in sports, and also how he views the Federal Reserve.”

Moore, a fellow at the Heritage Foundation and longtime conservative commentator, vowed to keep fighting Tuesday in an appearance on CNBC. He apologized over the weekend for his past comments about women, although he didn’t get into specifics.

The White House reiterated its support for Moore even as some Republicans appeared to be wavering on whether it was a good idea to move forward with his nomination.

“The president stands behind him,” said Kellyanne Conway, a senior Trump adviser, on Tuesday. “He’s somebody that gets the economy, and I guess we’ll continue to focus on that."

Moore did have some support in the Senate, with Sen. Rand Paul (R-Ky.) saying Tuesday that he was “for him,” but most Republican senators dodged reporters questions about Moore or sounded on the fence about whether he should be seriously considered for one of the nation’s top economic posts.

“Clearly there have been some developments that have been troubling with regards to the tax history, the child-care history and the comments I’ve made before still hold, which is it’s important for the Fed to be staffed and led by economists and folks that are not primarily partisan,” said Sen. Mitt Romney (R-Utah).

The Internal Revenue Service put a $75,000 lien on Moore for unpaid taxes, which Moore says he has now paid and were a result of a small mistake on his tax return a few years ago. Moore was also found in contempt of court in 2013 for failing to pay his ex-wife more than $330,000 in child support and alimony.

The White House has stood by Moore as news of his past legal troubles and writings have surfaced and caused a firestorm.

“I know him personally. I know he’s a good person,” Conway said. “I’m a strong, successful woman who’s worked with Stephen Moore for decades, and I know how he feels about women. I know how he treats women in the workplace."

Erica Werner and Seung Min Kim contributed to this report.