Sen. Joe Manchin (I., W.Va.) will not endorse Kamala Harris, saying the Democratic presidential nominee’s support for eliminating the Senate filibuster will “destroy our country,” CNN reported.

“Shame on her. She knows the filibuster is the Holy Grail of democracy. It’s the only thing that keeps us talking and working together. If she gets rid of that, then this would be the House on steroids,” said Manchin, who left the Democratic Party in May. Manchin, who still caucuses with Democrats, had signaled earlier this month that he would endorse Harris.

“That ain’t going to happen,” Manchin told CNN Tuesday. “I think that basically can destroy our country, and my country is more important to me than any one person or any one person’s ideology. … I think it’s the most horrible thing.”

Harris expressed her support for “eliminat[ing] the filibuster for Roe” in an interview with Wisconsin Public Radio on Tuesday. Following the Supreme Court’s 2022 decision to overturn Roe v. Wade, which gave states control over their own abortion laws, Harris has advocated for codifying Roe into federal law. Without a filibuster, Senate Democrats would only need a simple majority of 51 votes to pass the law rather than a 60-vote supermajority.

Harris previously backed gutting the filibuster, but her Tuesday comments mark her first statement on the issue since becoming the Democratic nominee, according to HuffPost.

Manchin said he expected Harris to walk back her stance on the filibuster, as she has done with her other progressive policies.

“She said she supported banning fracking too, and she changed that. I was hoping she would change this,” Manchin said.

Arizona Sen. Kyrsten Sinema, an Independent who caucuses with Democrats, also criticized Harris’s plan as “an absolutely terrible, shortsighted idea.”

“To state the supremely obvious, eliminating the filibuster to codify Roe v. Wade also enables a future Congress to ban all abortion nationwide,” Sinema said.