Schumer faced partywide backlash after caving to the Republicans in a March fight over government funding but has long been viewed with skepticism by the Left, the same voters who helped propel Mamdani to a decisive win against former Gov. Andrew Cuomo.
Schumer has attempted to manage his reputation by steadily inching leftward, and since March has taken a more combative tone against President Donald Trump. But Mamdani鈥檚 race is serving as a warning to Schumer that a young, progressive candidate can activate the base in a way that threatens even the most seasoned of politicians.
The Left has urged Rep. Alexandria Ocasio-Cortez (D-NY) to challenge Schumer in 2028, though it is not yet clear if she wants to remain in Congress or has presidential ambitions.
鈥淚t definitely opens up the door [for Ocasio-Cortez],鈥 said Hank Sheinkopf, a New York-based Democratic strategist and former adviser to New York Mayor Mike Bloomberg.
鈥淭hat generational shift is serious. It also tells the Democrats that sitting on the sidelines and waiting for Trump to fail is not necessarily a winning strategy,鈥 he added.
Sheinkopf said it was unclear whether Ocasio-Cortez could beat Schumer, but predicted she would 鈥済ive him a run for his money.鈥
Already, the longtime senator has been forced to reckon with how much to embrace or distance himself from Mamdani after taking a hands-off approach in the primary. Schumer, who lives in Brooklyn, declined to say how he voted.
After his victory, Schumer congratulated Mamdani in a social media post Wednesday for running a grassroots campaign that focused on the economy and affordability. But Schumer notably stopped short of making an endorsement.
鈥淚 have known [Mamdani] since we worked together to provide debt relief for thousands of beleaguered taxi drivers & fought to stop a fracked gas plant in Astoria,鈥 Schumer said. 鈥淗e ran an impressive campaign that connected with New Yorkers about affordability, fairness, & opportunity.鈥
Schumer added the two spoke and that he was 鈥渓ooking forward to getting together soon.鈥
There is a gulf between Schumer, the top Jewish elected official in U.S. history, and Mamdani over Israel. Mandami has defended the pro-Palestinian slogan 鈥済lobalize the intifada鈥 and is a critic of the Israeli government, though he denies he is antisemitic.
Schumer is also navigating Republican claims that Mamdani, who supports rent freezes and government-run grocery stores, is the new face of the Democratic Party. As the leader of Senate Democrats, he will be wary of tying his members to that brand too closely.
Still, Democrats believe Schumer ought to pay heed to what worked in Mamdani鈥檚 campaign and how it might reverberate in his own race. On top of representing a younger generation of Democrats, Mamdani ran a social media-savvy campaign on a message of change.
鈥淚t鈥檚 a signaling of, 鈥楾his is what we want, dummy.鈥 This is what voters are saying,鈥 said a New York Democratic source, who was granted anonymity to speak freely. 鈥淚f he is the leader of the party, which he is, he needs to be available to fight the good fight on the things that matter to us, and that often means standing up to Donald Trump. That often means outmaneuvering [Senate Majority Leader John Thune (R-SD)].
鈥淗e never does either one of those things. So as Democrats look to the future, I think they have to figure out what it鈥檚 going to look like and whether it makes sense to have him involved,鈥 the source added.
A New York-based Democratic strategist, also granted anonymity to speak freely, said it was likely too soon to tell the impact of Mamdani鈥檚 race on Schumer鈥檚 political future but noted the party鈥檚 base was already upset with his leadership under Trump鈥檚 second term.
鈥淟et鈥檚 be honest, Chuck Schumer was not in good stead with the vast majority of his own voters anyway,鈥 the strategist said. 鈥淚 would assume conversations are increasing in Schumer-land.鈥
Schumer attempted to carefully manage his relationship with the Left as he ascended the leadership ranks in the Senate. His constituent services have long included aggressive outreach to activist groups in his home state, while he endorsed policies like student debt cancellation ahead of his 2022 run.
For a time, progressives expressed cautious optimism that Schumer could be a partner after Democrats took back control of Congress in 2021. He signaled openness to weakening the filibuster and under President Joe Biden helped usher through a sweeping climate law.
But Schumer has never really shaken the establishment label that he鈥檚 carried throughout his five-decade career in politics, and Democrats have not forgotten that he at one time campaigned as a centrist.
In New York, Democrats have shown an openness to the law and order appeals of Republicans, allowing Republicans to make inroads in the House.
Rep. Laura Gillen (D-NY), a first-term member who represents a purple district on Long Island, slammed Mamdani for being 鈥渢oo extreme鈥 and running a campaign 鈥渂uilt on unachievable promises and higher taxes, which is the last thing New York City needs.鈥
Still, Schumer will need to advance out of a primary with a decidedly liberal electorate if he hopes to serve another term.
House Minority Leader Hakeem Jeffries (D-NY), to some extent, has similar challenges as Schumer to consider. He avoided much of the backlash in March, lining up his caucus to oppose the government funding bill.
SCHUMER AND JEFFRIES APPLAUD MAMDANI FOR WIN IN NYC MAYORAL PRIMARY RACE BUT STOP SHORT OF ENDORSING HIM
But he鈥檚 also been panned as an establishment politician by the same progressive lawmakers who endorsed Mamdani.
Jeffries offered a similarly worded statement just minutes before Schumer, congratulating Mamdani 鈥渙n a decisive primary victory.鈥 Jeffries also stopped short of an endorsement.
David Sivak contributed to this report.