Newsom Told Jake Tapper He Won't Run in 2028 if Kamala Harris Does. He Called a Primary Between Them 'Mutual Assured Destruction' and Said Republicans Would 'Enjoy the Hell Out of It.'

California Gov. Gavin Newsom said Monday that he will not run for president in 2028 if former Vice President Kamala Harris decides to run, removing himself in advance from what would have been the most closely watched matchup of the next Democratic primary.

"I wouldn't run if she ran," Newsom told CNN's Jake Tapper in an extended interview that aired Monday evening. The two spoke while fly-fishing at Newsom's in-laws' ranch in Montana, and the conversation ranged across his personal life, his record in Sacramento and the presidential ambitions he has spent much of the past year declining to confirm or deny. "I don't know if she runs, but we'll see," he added.

Asked why he would step aside for a fellow California Democrat, Newsom said a contest between the two of them would help no one but the other side. "Mutual assured destruction," he said, describing the effect on both candidates. "Electorally it's a gift from God for everybody else." Republicans, he said, would "enjoy the hell out of it." He pointed to the overlap in their political networks: "I know her base of supporters. I know her friends. The Venn diagram on that is just pure crossover. I wouldn't do that." In another exchange he put it more personally: "I wouldn't do that to her. I wouldn't do it to me."

Tapper pressed him on the obvious counterargument, that Harris already had her turn as the party's nominee in 2024 and lost, while Newsom has never run. Newsom did not dispute it. "That'd be the approach to the campaign, certainly," he said. "Pretty good one, actually. That's objectively true." But he said he would not make that case against her.

The comments land at a moment when both Californians have been behaving like candidates without saying so. Newsom recently traveled to South Carolina, which will hold the first contest of the 2028 Democratic primary calendar, and has toured other Southern states. Harris, who published a memoir of her 107-day 2024 campaign last September, has made her own stops in early primary states and said in July that she had "not made a decision." Her office did not immediately respond to CNN's request for comment on Newsom's remarks.

Polling gives Harris the early edge in a race that has not formally begun. The RealClearPolitics average of 2028 Democratic primary surveys puts her at 24.5 percent, with Newsom second at 13.5 percent and Transportation Secretary Pete Buttigieg, Rep. Alexandria Ocasio-Cortez and Sen. Jon Ossoff clustered within about five points behind him. Prediction markets tell a different story. On Polymarket, Ocasio-Cortez leads at 19 percent, followed by Ossoff at 16 percent, Newsom at 12.7 percent and Harris at 8 percent.

Newsom has said he will decide whether to run after the November midterms. His second term as governor ends in January, and California's term limits bar him from seeking a third. Voters will choose his successor on Nov. 3. He told Tapper that his wife, Jennifer Siebel Newsom, and their school-aged children would be central to any decision. "If they're not on board, that's a non-starter," he said, adding that one of his sons does not want him to run.

He also revisited his decision not to challenge President Joe Biden in 2024, when many Democrats were urging a younger alternative. "I wasn't ready," Newsom said. A candidate, he argued, needs a reason to run beyond the fact that an opening exists.

The pledge does not close the door on a Newsom candidacy. It makes his path contingent on a decision Harris has not made and may not make for months. If she stays out, the governor who has spent a year building a national profile would enter the race as the highest-polling Democrat in the field. If she gets in, he says, he will not.