Something significant happened in New York City on Tuesday night, and it would be a mistake to dismiss it as local politics. Zohran Mamdani, the city’s new socialist mayor, endorsed three candidates in Democratic congressional primaries — and all three won. That includes the unseating of two incumbents, both of whom were broadly supportive of Israel. Among the winners was Darializa Avila Chevalier, a candidate who had made headlines for saying she used the American flag as a wash rag and for expressing support for abolishing schools. Mamdani had made his opposition to Israel a key litmus test throughout the campaign, and in its closing days called AIPAC “monsters” — borrowing a phrase from a Marxist philosopher — and declined to condemn a coffee shop owner who smeared the Jewish candidate Dan Goldman as someone who sipped “genocide juice.”

What does this tell us? It tells us that the radical left is no longer a fringe element within the Democratic Party — it is increasingly setting the agenda. The three races were closely watched nationally as a test of the young mayor’s strength, and many seasoned New York political hands were shocked by the clean sweep. Moderate Democrats did hold on in a few districts — Rep. Ritchie Torres, a staunch supporter of Israel, handily defeated a primary challenge in the Bronx — but the overall results sent an unmistakable message about where Democratic energy currently flows. For those who care about Israel’s standing in American political life, Tuesday’s results are a sobering data point.