WASHINGTON (AP) — Former Vice President Kamala Harris said Monday evening that she regrets not expressing her concerns about then-President Joe Biden running for a second term when a majority of Americans felt he was too old for the job.

"I have and had a certain responsibility that I should have followed through on," Harris told Rachel Maddow on MSNBC in her first live television interview since the election.

Such a conversation, even if it happened privately and behind the scenes, would have been an extraordinary breach in a relationship between a president and vice president.

Harris' comments expand on a passage in her book, “107 Days,” that looks back on her experience replacing Biden as the 2024 Democratic presidential nominee after he dropped out of the race. Harris ultimately lost to Republican candidate Donald Trump.

In the book, Harris wrote that everyone in the White House would say “it's Joe and Jill's decision” about running for reelection, referring to the president and first lady.

“Was it grace, or was it recklessness? In retrospect, I think it was recklessness,” she wrote. “The stakes were simply too high. This wasn’t a choice that should have been left to an individual’s ego, an individual’s ambition. It should have been more than a personal decision.”

In her interview with Maddow, Harris said, "when I talk about the recklessness, as much as anything, I'm talking about myself.”

Harris said in the interview she was concerned that “it would come off as completely self-serving” if she had counseled Biden not to seek reelection. She had competed against him for their party's 2020 nomination, and she was well positioned to run again.

A representative for Biden declined comment.

Although Harris wrote that she wasn't worried about Biden's ability to continue doing the job, she had concerns about him campaigning.

“His voice was no longer strong, his verbal stumbles more frequent,” she wrote. Before Biden dropped out, there were plans for him to run a White House-centric campaign while Harris did more traveling. A week after Biden's disastrous debate against Trump, she wrote that “he felt so frail.”

Harris turns 61 next month, and she hasn't detailed her future plans. Asked about running for president again in 2028, Harris said “that's not my focus right now.” She's already passed on an opportunity to run for governor of her home state of California.

She backed a plan by Gov. Gavin Newsom to redraw congressional districts to counteract a similar plan by Republicans in Texas that was intended to help Trump keep control of the House in next year's midterms.

“We tend to play by the rules," Harris said. "But I think this is a moment where you got to fight fire with fire.”

She spoke harshly about Trump in the interview, criticizing him as acting like “a tyrant” and “Communist dictators,” saying “that's what we're dealing right now in Donald Trump.”

Harris also pointed the finger at business leaders who she accused of capitulating to the president.

“These titans of industry are not speaking up,” she said.

Maddow referenced a passage in Harris' book where she wrote that Pete Buttigieg was her first choice for vice president but she was worried that Americans weren't ready to vote for a ticket featuring a Black woman and a gay man.

“It's hard to hear ... he couldn't be on the ticket, effectively, because he was gay," Maddow said.

Harris said “it wasn't about any prejudice on my part” but “we had such a short period of time, and the stakes were so high.”

“It made me very sad, but I also realized it would be a real risk,” she said. Harris conceded “maybe I was being too cautious.”

Buttigieg told Politico he was “surprised” by the passage in the book about him. He also said he believes in “giving Americans more credit."

Former Vice President Kamala Harris (AP Photo/File)