I live in New York City, so Zohran Mamdani is my mayor. On Tuesday, you may have seen Mamdani release a video in which he said Israeli Prime Minister Benjamin Netanyahu is a war criminal and is not welcome here. He called on the federal government to join the International Criminal Court and execute a warrant for his arrest.

Here is why this stunt – and make no mistake, that is what it was – is such a troubling sign about where American politics is headed. This is about so much more than Israel and its prime minister.

When he ran for mayor, Mamdani promised repeatedly to arrest Netanyahu if he ever came to NYC. He did so even though every serious legal scholar said no mayor had the authority to arrest a foreign head of state. Foreign policy is the domain of the federal government – period. Mamdani is smart enough to know this, so it seems he was willing to peddle a complete lie because he knew a certain segment of the Democratic primary electorate would eat it up.

It gets worse. By law, visiting foreign leaders are protected by the U.S. Secret Service, and the security they provide at the UN General Assembly – which Netanyahu and over 100 other foreign leaders will attend in September – is even more significant.

So here is a question for Mayor Mamdani. What was the plan for how to arrest Netanyahu? Was the NYPD supposed to demand the U.S. Secret Service hand over the Prime Minister of Israel? When the Secret Service said no, what next? Was the NYPD supposed to pull its weapons?

To ask these questions is to instantly understand how utterly ridiculous and reckless Mamdani has been. I won’t even get into what Mamdani actually said in his video, much of which was either outright lies or propaganda that came directly from organizations linked to Hamas.

What Mamdani did this week was truly unprecedented.

The former Libyan dictator Muammar Gaddafi addressed the General Assembly in 2009 and spent a week in New York City. He’s one of many terrible dictators who attended the event and never got arrested because no local official had the authority to do so.

Two big lessons follow from Mamdani’s stunt and both of them are larger than one mayor.

The first is that Mamdani’s video represents the ascent of the performative extremism that increasingly defines our politics. That material used to circulate outside the halls of power. Now it comes from inside the City Hall of America’s largest city.

This is what people mean when they say extremism is being mainstreamed, and it is not confined to one party. Marjorie Taylor Greene spent years running the identical playbook from a seat in Congress, treating a House office as a content studio, and she was rewarded for it with attention, money, and influence right up until she resigned in January. The lesson both parties have absorbed is that the behavior works.

The second lesson is that many of our leaders increasingly don’t understand their job. New York City spends more per student than any city, yet our public schools deliver terrible results. Our poverty rate – at 26% – is twice the national average. The main bond rating agencies have downgraded NYC’s fiscal outlook from “stable” to “negative.”

It is a long way of saying the mayor of New York City has plenty of problems to tackle without spending his time making empty and dangerous threats to foreign leaders.

Our politics is getting more extreme, and our leaders more performative for a simple reason: They are rewarded for it, with attention and votes.

The only way this will change is if America’s commonsense majority starts using our votes to keep these kinds of leaders out of office.