GOP 2024 presidential candidate Nikki Haley called ailing Sen. Dianne Feinstein a prime example of why we need mental competency tests for politicians, urging the 89-year-old Democrat to resign from the Senate.

In an opinion piece published on Fox News Monday, Haley, a onetime U.S. ambassador to the United Nations in Donald Trump s administration, called Feinstein a trailblazer whos made an indelible mark in public service.

But its been obvious for quite some time that shes in significant mental and physical decline, Haley wrote.

I agree with several congressional Democrats who say Feinstein should resign immediately and let someone else who is able to do the job take over, she continued.

Feinstein, who was hospitalized with a case of shingles in February , is still recovering at home in San Francisco. She has pledged to come back to Washington once her doctors clear her, but has yet to provide a date for her return.

The California Democrat is not running for reelection, but has said she intends to serve the remainder of her term.

But some progressive Democrats, including Rep. Ro Khanna (D-Calif.) , have grown impatient by Feinsteins absence and called on her to step aside out of respect for the American people.

Her lengthy absence has also been a challenge for Democrats on the Senate Judiciary Committee, where Feinstein is a member, and has raised concerns that it could stall President Joe Biden s legislative priorities, including getting his judicial nominees approved. While Feinstein bowed to pressure and asked Senate Majority Leader Chuck Schumer (D-N.Y.) to appoint a temporary replacement for her on the committee, Republicans refused to allow the request.

Her absence has also hindered the panel from potentially compelling Supreme Court Chief Justice John Roberts to testify before the committee with regard to the ethics rules governing the justices, following revelations that Justice Clarence Thomas accepted lavish gifts from a GOP megadonor.

In her piece, Haley said Feinstein has demonstrated she no longer has the ability to perform her Senate duties.

At 89 years old, she is a prime example of why we need mental competency tests for politicians, Haley wrote.

Haley first floated the idea of politicians taking such exams when she launched her presidential campaign in South Carolina , where she previously served as governor, in February.

She called for mandatory term limits and mandatory competency testing for politicians over 75.

Her remarks were also interpreted as an apparent jab at Trump, 76, and Biden, 80.

Biden launched his reelection campaign last week. If successful, he would be 86 at the end of his second term.

In an interview with Fox News last week, Haley suggested it was possible Biden would die in the next five years, and therefore a vote for him would effectively be a vote for Vice President Kamala Harris.

If you vote for Joe Biden you really are counting on a President Harris, because the idea that he would make it until 86 years old is not something that I think is likely, Haley said.