Zohran Mamdani did not just win New York's Democratic mayoral primary last year – he may have reshaped the political landscape of the largest US city.All three congressional candidates he endorsed won their Democratic primaries on Tuesday, defeating incumbents and establishment-backed rivals. The three candidates are also expected to win their Democrat-leaning districts, which would also place three Mamdani allies in Congress come January.Their campaigns, in a city that hosts an annual Israel Day parade, were marked by strong opposition to US military support for the Israeli government amid the war in Gaza, and their victories could signal a broader shift within the Democratic Party.Brad Lander, a former city comptroller and self-described “liberal Zionist”, defeated Representative Dan Goldman after turning their contest into a referendum on Israel. Mr Lander criticised Mr Goldman for opposing legislation to block arms sales to Israel and for refusing to call its military campaign in Gaza a genocide.Democratic socialist Darializa Avila Chevalier defeated Representative Adriano Espaillat, relentlessly attacking him for accepting donations from the powerful American Israel Public Affairs Committee (Aipac).A third democratic socialist, Claire Valdez, a first-term New York state lawmaker, also secured the Democratic nomination for an open House seat covering parts of Brooklyn and Queens.At her victory celebration, chants of “Free Palestine” broke out as Mr Mamdani made his way through the crowd, greeting supporters.Ms Valdez used her victory speech to highlight her progressive platform, asking supporters: “Are we ready to free Palestine? Are we ready to abolish ICE? Are we ready to win Medicare for All, housing for all and unions for all?”The results underscore a significant shift within New York City's Democratic Party. Positions that were once considered politically risky – particularly strong criticism of Israel in a city with a large Jewish population – no longer appear to be a liability. Instead, the victories of several progressive candidates suggest the party's stance on Israel is evolving rapidly, reflecting changing priorities among young Democratic voters.Last week, voters in Washington gave a primary win to Democratic socialist Janeese Lewis George in the mayor's race, making her almost certain to become the US capital's next leader.Republicans in the Make America Great Again movement and moderate Democrats reacted sharply to the New York election results.Republican Congresswoman Elise Stefanik wrote on X: “Gotham has fallen. The mass exodus out of New York will continue apace. I call it the Blue Exodus.” She argued that the victories of what she called “Marxist Socialist candidates” would further damage New York City and warned that the “virulent anti-Semitism” in some campaigns was “dangerous not only to Jews, but to every American”.Democratic Senator John Fetterman slammed the results of Tuesday's elections, telling Fox News, “This has become the dancing days of the dirtbag left.”Mr Fetterman, whose growing support for President Donald Trump has put him at the more conservative end of the Democratic spectrum, said some of the winning candidates hold views he considers extreme. “Some of these candidates are outrageous. You have candidates that want to abolish ICE, abolish police, abolish the border,” he said. He also criticised Mr Mamdani, accusing him of mourning Al Jazeera journalist Ahmed Wishah, who Israel said was a Hamas sniper killed in an air strike. Mr Fetterman argued that the candidates who won represent the party's “full pro-Hamas wing” and said they have declared “war on regular Democrats”.Meanwhile, New York Attorney General Letitia James criticised Mr Mamdani and some of the candidates he endorsed, telling CNN that some of them do not fully understand the communities they seek to represent and are disconnected from the history and struggles of many city districts.Ms James said she and other Democratic leaders were “disappointed” in Mr Mamdani. “All of us are a little frustrated with the Democratic Party. But you don't blow it up. That's what Maga has done,” she said.