At her confirmation hearing Thursday, Sen. Mitt Romney said Julie Su, the Biden administration’s pick for Labor secretary, was “biased” and that promoting her “makes no sense.”

Su may have trouble clearing the Senate nomination process, as several swing senators still haven’t said whether they’ll support her nomination, including Democratic Sens. Joe Manchin of West Virginia and Jon Tester of Montana, and independent Sen. Kyrsten Sinema of Arizona.

As head of California’s labor department at the beginning of the COVID-19 pandemic, Su oversaw the department at a time when applications for unemployment increased significantly, as did fraud.

A state audit found there were more than $30 billion in fraudulent claims paid out in 2021, much of the money for which came from the federal government.

“Your record there is so severely lacking, I don’t know how in the world it makes sense for the president to nominate you to take over this department,” Romney said at the hearing.

Romney said the sum was “about as much as we provided in military aid to Ukraine,” and he laid the blame for the fraud on Su.

“The buck stops at the top. You’re the person running UI. You’re the person that decided to waive the guardrails,” he said. “The idea of promoting a person who’s had that experience to a position of leadership of the entire Department of Labor makes no sense at all.”

Su said that most of the fraud occurred in the pandemic unemployment insurance program, which “did not have the safeguards that regular unemployment insurance does.”

Su is currently the acting secretary, and was previously the deputy secretary, and she oversaw the federal department at a time when reports of child labor law violations increased significantly, primarily because of issues related to undocumented children.

A New York Times report said 250,000 migrant children have come into the U.S. over the past two years, with “thousands” ending up in unsafe or difficult jobs.

At the confirmation hearing, Romney asked Su about the trafficking of unaccompanied minors in “illegal labor markets across the country.”

“Your department wrote last year that violations have increased by some 70% since 2018. Was that communicated to the White House prior to this year?” he asked.

“I don’t know the answer to that question,” Su replied.

Business groups have raised concerns over Su’s positions on freelance workers and franchisees, including the International Franchise Association, according to Bloomberg. At the hearing, Su said she was the daughter of immigrants who owned a pizza franchise. Before her government service, Su was a civil rights attorney.

Su has received significant support from unions. The Wall Street Journal reported that labor giant AFL-CIO spent six figures on ads to promote her.

At the hearing, Romney criticized Su for meeting regularly with union officials, but rarely with business associations.

“During your last two years at the Department, the public calendar shows that you had a standing meeting with unions on a regular basis, but until six weeks ago, you’d not met with any business associations,” he said. “I guess it’s really hard to understand how when we think about putting two groups together, getting to the compromise and negotiating, how we could have any confidence that you’d be seen as an unbiased, neutral arbiter.”

In 2021, when Su was appointed to the deputy labor secretary position, Romney did not vote to confirm her either in committee or on the Senate floor, his spokesperson said.