Former Vice President Joe Biden said the most “damaging” part of President Trump’s tenure in the White House has been the appointment of Justice Neil Gorsuch to the Supreme Court.

In an interview with the podcast “Pod Save America,” Biden said he would fight any future Supreme Court nominee of Trump’s. The president named Gorsuch to the high court last year to fill Justice Antonin Scalia’s seat after his death in 2016.

“I would work like the devil if I were in the Senate, if we had a Democratic Senate, to keep [another] Gorsuch from going on the court,” Biden said. “The single most damaging thing thus far, short of what may happen to our foreign policy, was Gorsuch going to the court.”

Trump has reportedly predicted he’ll name up to three more justices to the Supreme Court by the end of his first term. In addition to Gorsuch, the president has reportedly speculated he’ll name replacements for Justices Anthony Kennedy, Ruth Bader Ginsburg, and Sonia Sotomayor.

Ginsburg, who recently turned 85, and Kennedy, who turns 82 this summer, are often the subject of retirement rumors. Trump reportedly believes Sotomayor will retire due to her health. The justice has type-1 diabetes.

None of the justices, however, have indicated they’ll step down from the bench.

After Scalia’s death, then-President Barack Obama nominated Merrick Garland of the D.C. Circuit Court of Appeals to fill his seat. But Republicans, led by Senate Majority Leader Mitch McConnell, R-Ky., refused by consider Garland’s nomination during an election year.

Biden criticized Republicans for that move.

“The next [court appointee] is gigantic. Gigantic. And I think everything should be done and can be done within the constitutional parameters," he said. "But guys, if we start to add on to disregarding the Constitution, if we continue to strike back by using the same methods he used of abusing the system, by prostituting the democratic processes …”

