Rep. Adam Schiff, D-Calif., on Sunday said Vice President Kamala Harris could “overwhelmingly” win against former President Donald Trump but that President Joe Biden must decide whether he will remain in the race as the Democratic Party’s nominee amid backlash over his disastrous debate performance.

Asked about polling that showed Harris outperforming Trump if she replaced Biden, Schiff said on NBC News’ “Meet the Press” that he thought she would be a “phenomenal president.”

“I think she has the experience, the judgment, the leadership ability to be an extraordinary president,” Schiff told moderator Kristen Welker.

Pressed again by Welker on whether Harris could win “overwhelmingly” against Trump, Schiff said he thought “she very well could win overwhelmingly” before stressing that it’s up to Biden to decide the fate of his presidential campaign.

“Before we get into a decision about who else it should be, the president needs to make a decision whether it’s him,” he said.

Asked whether Biden should drop out and pass the torch to Harris, Schiff again argued that it’s up to Biden to make that call.

“I think Biden should take the time talk to people outside of his immediate circle, talk to people he respects, people with objectivity, people with distance, and make the right decision for the country,” he said. “And I’m confident Joe Biden has always made the fundamental distinguishing distinction between he and Donald Trump.”

Schiff also raised concerns about the president’s standing against Trump in the general election, noting the president’s age.

“Given Biden’s incredible record and given Trump’s terrible record he should be mopping the floor with Donald Trump,” Schiff said. “It should not be even close, and the reason it is close is the president’s age.”

Schiff also said Biden’s interview with ABC News that aired on Friday wasn’t enough to quell mounting concerns from Democrats about his mental fitness.

“The interview didn’t put concerns to rest. No single interview is going to do that,” he said. “And what I do think the president needs to decide is, can he put those concerns aside? Can he demonstrate to the American people that what happened on the debate stage was an aberration, that he can and will beat Donald Trump.”

Pressed on whether he thinks Biden should take a cognitive test after he refused during his ABC News interview to commit to taking one, Schiff said he’d be happy if both Biden and Trump were willing to take a test.

“I think, frankly, a test would show Donald Trump has serious illness of one kind or another,” he said. “But ultimately, the decision is going to come down to what Joe Biden thinks is best, and if his decision is to run, then run hard and beat that S.O.B. And if his decision is to pass the torch, then the president should do everything in his power to make that other candidate successful.”

Schiff’s answers come after Biden’s interview with ABC News did little to assuage concerns from Democrats who have called for Biden to step aside after his lackluster debate performance last month. Front-line Democrats who spoke to NBC News say they fear that his debate performance has done irreversible damage to his candidacy.

In his interview with ABC News, the president sought to reassure voters that he remains the best candidate to beat Trump in November, arguing that he had a “bad night” at the debate as he sought to tamp down mounting concerns over his age and mental fitness.

Biden remained publicly defiant in the face of calls from some Democrats to drop out of the race, repeatedly saying that only “the Lord Almighty” could convince him to end his bid for a second term in office.