“What a night for the Democratic Party” is how Governor Gavin Newsom put it after the results rolled in on Tuesday. The Californian reckons the Democrats are “a party that is in its ascendancy, a party that is on its toes, no longer on its heels.” Even accounting for partisan hype, it’s hard to discount Mr. Newsom’s glee. Democrats won the governor’s mansions in Virginia and New Jersey, the mayoralty at New York City, and races all over.

Mr. Trump took to Truth Social to offer his analysis: “TRUMP WASN’T ON THE BALLOT, AND SHUTDOWN, WERE THE TWO REASONS THAT REPUBLICANS LOST ELECTIONS TONIGHT.” Maybe so. Mr. Trump, though, is unlikely to be on another ballot ever again — and certainly not in the midterm elections next year. Politico calls the results a “rout” and an “an unambiguously brutal referendum” on the president.

The Democratic victories can all be qualified. New Jersey is a blue state, and Gotham is an ultramarine city. Mr. Newsom’s redistricting referendum passed in California, hardly a battleground. Abigail Spanberger’s victory in Virginia is possibly a better bellwether, though President Biden won the Old Dominion in 2020 and President Obama won it twice. Still, the size of the Democratic wins suggest a wakeup call for the GOP. 

Mayor-Elect Zohran Mamdani’s victory, alone, could function as something between an alarm clock and a fire alarm. For the mainstream party, for starters. While the prospect of socialist schadenfreude might seem appealing to New Yorkers of a conservative bent, the failure of the city’s Republicans to run a credible candidate for mayor means that they too bear a share of blame for the ascendancy of Mr. Mamdani.

Brewing in the background is the rising tide of antisemitism on the right, which cannot but harm the party’s chances of erecting a big tent. The more the likes of Tucker Carlson and Nick Fuentes seize the spotlight, the harder it becomes for Republicans to paint the likes of Mr. Mamdani as the greater threat to Jews and to bedrock American values. Feature the failure of Vice President Vance to distance himself from the anti-Jewish factions. 

Americans voted for Mr. Trump to secure the border, lower inflation, and claim common sense ground in the culture wars. He can claim success on several fronts, and his foreign policy achievements are shaping up to be formidable. His more outré uses of executive power, though — prosecuting political rivals, say — appear to be turning off voters, as they did when the Democrats tried that strategy. 

With the president sporting a 39 percent approval rating, Republicans can hardly afford to be complacent in respect of the signals from Tuesday’s vote. Politico marvels at the “spooks-to-socialists coalition” who won — an allusion to Mr. Mamdani and Ms. Spanberger, a former officer in the CIA. Not long ago it was Mr. Trump who could boast of his big tent. Now his opponents are feeling good about the breadth of their canvas.