‘The rest of the world is watching.’ London Mayor Sadiq Khan cautions Americans against reelecting Trump.

NEW YORK — London Mayor Sadiq Khan isn’t passing up a chance to reignite his feud with Donald Trump.

The outspoken leader denounced Trump and urged people to vote for Kamala Harris as he sat down Tuesday for an interview with POLITICO in the former president’s hometown.

“What I’d say in a respectful way to Americans is: I don’t think you realize that the rest of the world is watching because we’ve got skin in the game,” he said.

Khan has made no secret that he is no Trump fan. The mayor has called the former president a racist, sexist and homophobe, and the two have sparred in bursts over the years. Trump memorably called the mayor a “stone-cold loser” in 2019.

Khan warned Tuesday that a second Trump presidency would have much farther-reaching effects than Americans may realize.

“What happens in America is the metronome … that sets the beat of what happens across the globe,” the three-term mayor said. “It sets the beat for how other politicians behave in an election campaign.”

Khan spoke with POLITICO in New York, where he was attending events around the United Nations General Assembly. The global gathering, he said, shines a spotlight on issues and interests shared by the U.S., the United Kingdom and other countries.

Trump’s politics and positions — from withdrawing once again from the Paris climate accord to his refusal to accept election results in 2020 and his rhetoric about women and immigrants — are dangerous, Khan said.

The left-leaning Labour Party member has championed Harris as his choice for president in a way that others in leadership around the United Kingdom, including Prime Minister Keir Starmer, cannot.

He urged Americans to consider the impact of Trump’s first term before giving him another.

“Make sure you’re registered to vote and make sure you vote,” he said. “Because the election that happens on Nov. 5, in my view, is the most important election in my lifetime.”

The Trump campaign did not immediately respond to a request for comment.

Khan also discussed the rioting, arson and looting that gripped the United Kingdom over the summer, sparked by false reports, amplified on social media, that a Muslim asylum seeker killed three children in Southport.

British and American leaders must address concerns about healthcare, housing and education, “not to play on people’s fears,” Khan said. “The oldest trick in the book is to blame the other. The oldest trick in the book is to pick on one community and one minority, manufacture a situation where they’re blamed for the problems.”

The mayor, whose Labour Party is now in power after 14 years of Conservative rule, earlier in the interview defended Starmer, whose first months in office have been plagued by low approval ratings, a scandal over his accepting of gifts from a donor and his cutting of winter fuel allowances for pensioners.

Starmer is laying the foundation for a stronger economy and future, Khan said

“It has been tough. Of course, it’s tough. Running things is tough, but I’d rather Keir Starmer make those tough calls, tough decisions, to be straight with the British people now, rather than having things being covered up and buried away,” Khan said. “And that means sometimes making decisions that in the short term are unpopular, but leading to medium-term, long-term benefits.”