Rep. Nancy Mace warned Friday of President Biden's "mental decline" after the president walked off an MSNBC set before the live interview had ended. On "Fox & Friends First" Friday, Mace said "there's no denying" what is happening with the president and it's becoming "difficult to watch."

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REP. NANCY MACE: Well, certainly we're seeing his cognitive decline. There's no denying that. But what you see here, what you've seen over the last couple of weeks and months, you've seen a guy like Donald Trump take tough interviews, take tough questions, do tough town halls, and Joe Biden can barely pass a softball interview. And so the differences are so stark in contrast, right now. I don't know how anybody goes along with what Joe Biden is trying to sell. It's very, as a mom with aging parents, it's very difficult for me to watch him be forced through this thing. He shouldn't be president, just that mental decline is really awful to watch.

President Biden could not wait until the commercial break to flee the set of a live televised interview with MSNBC's Nicolle Wallace. 

Biden granted the liberal host a rare live sit-down on Thursday, which largely focused on his reaction to the Supreme Court's historic decision to strike down affirmative action. 

After nearly 20 minutes of softball questions, Biden got up from his chair and took the scenic route off the MSNBC set, walking behind Wallace as she teased analysis of her interview to viewers. 

"Fox & Friends" host Brian Kilmeade said the president continues to struggle with where to go when his speeches and other events are over. 

"This president has the hardest time leaving and coming onto a stage or a set. … The way he left is bizarre," he remarked, as co-host Steve Doocy mentioned there were a "million" questions Wallace failed to ask the president.

Fox News' Joseph A. Wulfsohn contributed to this report.