NEW YORK (AP) — Not long ago, New York City Mayor Zohran Mamdani was demonized by leaders of both political parties. Today, just six months after taking office, the 34-year-old democratic socialist's political strength is surging.

Always a darling of the far left, he has earned praise from both President Donald Trump and former Democratic critics like New York Gov. Kathy Hochul. He has emerged as the face of the region's sports renaissance. And days before New York's primary elections, Mamdani is testing the limits of his newfound political muscle in a bid to reshape the Democratic Party — in his state capital and in Washington — even if it means challenging his own party's leadership.

Mamdani will join Sen. Bernie Sanders, I-Vt. at a get-out-the-vote rally in Brooklyn on Thursday. The event is designed to elevate a slate of candidates aligned with Mamdani's values, including two running against Democratic incumbents in Tuesday's primary.

"He's seeing that opportunity — that we can radically change the Democratic Party," said Faiz Shakir, a senior adviser to Sanders and a friend of Mamdani's. "Like Bernie, he's not saying I'm doing this out of spite against you, dear leadership. He's saying, I am supporting these candidates who have a better vision, and I am prepared to lose if it has to be the case."

The Mamdani slate

Establishment Democrats are not pleased with the mayor's decisions.

Mamdani endorsed political organizer Darializa Avila Chevalier over Rep. Adriano Espaillat, the chairman of the Congressional Hispanic Caucus, in New York's 13th District, which includes parts of upper Manhattan and the Bronx.

He is also backing former New York City Comptroller Brad Lander, who is running against incumbent Rep. Dan Goldman in New York's 10th District. And in New York's 7th, he's supporting democratic socialist state Assembly Member Claire Valdez against outgoing Rep. Nydia Velazquez's handpicked successor.

The Mamdani slate, in addition to several state Assembly candidates, will be featured at Thursday's rally.

READ MORE: The price tag of overcoming a Trump endorsement, and other takeaways from Tuesday's primaries

Valdez says the election is about advancing the political movement Mamdani ignited on his way to City Hall.

"Right now there's really mass dissatisfaction with the way the party leadership has been operating and not standing up strongly enough to Trump," she told The Associated Press, contrasting the malaise to the way the mayor energized voters last year.

She said she hopes to "bring a partner to Zohran to Washington."

Valdez's primary opponent, Brooklyn Borough President Antonio Reynoso, said he feels like the underdog in the race, even though he was endorsed by the outgoing incumbent. He said Mamdani "has a celebrity status that we haven't seen the likes of since I've been alive."

"He's going to be our champion for the foreseeable future and he's doing a great job, and when he says that he's endorsing someone, it matters," Reynoso said in an interview. "I believe that this community has seen me work, they know I'm a progressive champion, and in any other circumstance I would be a favorite to win this race, but I'm not because he has tipped the scale."

WATCH: Zohran Mamdani on his bold agenda, tackling Islamophobia and working with Trump

The candidates are largely aligned on the biggest issues, although there are modest differences.

Israel's war with Gaza has featured heavily among the Mamdani slate, with Lander, Valdez and Avila Chevalier casting their Democratic opponents as too soft on Israel. They're echoing the mayor's steadfast criticism of the country's leaders and harnessing what they believe could be a driving force in this year's elections.

The mayor's candidates have also sought to replicate much of the platform that sent him to City Hall, focusing on the city's high cost of living and framing themselves as fresh faces not beholden to powerful business interests.

The view from Washington

On Capitol Hill, Democrats are pleasantly surprised that Mamdani has become less of a political liability for the party in swing district seats than they once feared.

But Mamdani's endorsements have aggravated intraparty fissures, especially among moderates who worry that Mamdani's far-left brand may eventually tarnish the entire party.

And House Minority Leader Hakeem Jeffries, a fellow New Yorker, has tried to push back against the Mamdani-backed democratic socialist challengers, endorsing and campaigning for the embattled incumbents in a proxy fight with the mayor.

But Jeffries and Mamdani have opted to wrestle only in primaries rather than bicker publicly and feed into GOP narratives of Democratic disarray.

"Democrats must understand, and both the leader and Mamdani appreciate this, how to yell in areas where we agree and whisper in areas where we diverge," said Antjuan Seawright, a Democratic strategist who works with House Democrats.

WATCH: How a Mamdani win could change New York City and the Democratic Party

For now, Jeffries' allies acknowledge that Mamdani has energized Democratic voters and may be able to reach some Americans who have checked out of the political process. They also prefer that Mamdani is hyper-focused on New York City's governance rather than traveling across the country nationally.

Republicans, however, have plans to elevate Mamdani's profile whether Washington Democrats want them to or not.

The GOP hasn't made Mamdani a central feature of its broader national messaging as it once threatened, but Republican operatives have sought to link Mamdani to Democratic House candidates in swing districts across California, Colorado and Wisconsin. They also believe the specter of the New York City mayor will loom large in pivotal House races in New York and New Jersey.

The Republican bet is that vulnerable Democrats cannot afford to break with Mamdani too cleanly for fear of alienating progressive voters, even as they cast him as a radical.

"Zohran Mamdani's socialist brand is as toxic as it comes," said Mike Marinella, a spokesperson for the National Republican Congressional Committee, House Republicans' campaign arm. "And during a time when Democrats don't have a leader or a message, he's exactly the kind of bogeyman we can use against Democrats to truly show who is leading their party and the crazy policies they all support."

Meanwhile, Sanders' adviser Shakir encouraged the Republicans to try. He noted that Sanders mentions Mamdani in almost every speech as he tours the nation rallying voters ahead of the midterms.

"The crowd just goes nuts," Shakir said. "He certainly is not a political liability."

Brown reported in Washington.