President Trump has weighed in on New York Gov. Kathy Hochul's endorsement of Zohran Mamdani in the New York City mayor's election. 

Hochul made the endorsement as Mamdani continues to dominate polls. A new CBS News New York poll shows Mamdani with a 15 point lead in the mayor's race. Hochul's endorsement could have major repercussions. 

Mamdani was out in the Bronx Monday, shaking hands with striking workers as he basked in the unexpected endorsement by the moderate Democrat, who decided that despite disagreements on several issues, he's her top choice to run the city. 

"I'm excited to welcome Governor Hochul to our movement, and to show the partnership at hand between City Hall and Albany in fighting to make the most expensive city in the United States of America affordable," Mamdani said. 

Hochul defended her decision. 

"I think what put me over the top was this discussion about Donald Trump inserting himself into our local election, trying to put his thumb on the scale, and perhaps clear the field for his designated choice. And that was very disturbing and frightening to me," Hochul said. 

"How can such a thing happen?" 

Writing on social media, Mr. Trump again referred to Mamdani, a democratic socialist and the Democratic nominee, as a "Communist." 

He called Hochul's endorsement of Mamdani a "rather shocking development, and a very bad one for New York City. How can such a thing happen? Washington will be watching this situation very closely. No reason to be sending good money after bad!" 

It wasn't immediately clear what federal money the president was referring to. 

Hochul announced her endorsement of the Queens assemblyman in a New York Times op-ed Sunday night. 

She reiterated Monday they don't see eye-to-eye on all things. 

"I've made it very clear that we have differences, but I also believe that he brings the sense of optimism and the can-do spirit," Hochul said. "A positivity that I think our city needs at this time. And we all know there's a lot of work that occurs at the state government level once the budget starts and our priorities are unfolded, and I want to continue to focus on affordability, public safety."

NYC mayoral candidates react 

Adams was distressed by Hochul's endorsement of Mamdani. 

"There are 8.5 million New Yorkers. The governor has one vote. Let's be clear on that," Adams said. 

Republicans were downright gleeful. Sliwa called Hochul's endorsement a "tremendous flip flop," saying she "collapsed like a cheap camera and has thrown in with the Zohranistas." 

Sliwa said he was determined to remain in the race. 

"I am staying in the race to the end," Sliwa added. 

A likely challenger to Hochul in next year's race for governor pounced on the endorsement. 

"Well, Kathy Hochul is the worst governor in America, and it was only a matter of time before she bent the knee for this raging anti-Semite communist. The reality is Kathy Hochul owns Zohran Mamdani's position to defund the police, to abolish our law enforcement, to abolition prisons," Rep. Elise Stefanik said. "It is outrageous."

CBS News New York has reached out to Cuomo for a response to Hochul's endorsement. We have not heard back.

Hochul's endorsement is significant and may help Mamdani win the backing of other top Democrats who have been wary of showing support, such as Sen. Chuck Schumer and Rep. Hakeem Jeffries.

Political experts are scratching their heads, predicting Hochul's endorsement will hurt her reelection chances. 

"Why would you do this?  You just barely won your last election by 300,000 votes. You lost 52 out of 62 counties," political analyst JC Polanco said. "Why would you do this and hurt your chances with the suburbs around New York City? The only thing that makes sense is the fear that is the fear that the democratic socialists of America are more popular than ever before, will sit this election out and may not support her in a reelection." 

In her op-ed, Hochul said she and Mamdani "don't see eye to eye on everything," adding they may "disagree honestly and argue passionately." 

"In the past few months, I've had frank conversations with him. We've had our disagreements. But in our conversations, I heard a leader who shares my commitment to a New York where children can grow up safe in their neighborhoods and where opportunity is within reach for every family. I heard a leader who is focused on making New York City affordable — a goal I enthusiastically support," Hochul wrote. 

Hochul said Mamdani's focus on affordability is the "No. 1 concern" she shares with him. 

Hochul wrote that she urged Mamdani "to ensure that there is strong leadership at the helm of the NYPD" and also spoke with him about "the need to combat the rise of antisemitism urgently and unequivocally." 

Mr. Trump's previous involvement in the NYC mayor election

It's not the first time Mr. Trump has weighed in on the four-way mayor's race. He previously said he would like to see a one-on-one election. 

Sources told CBS News New York the Trump administration has been exploring possible job offers for both incumbent Mayor Eric Adams and Republican nominee Curtis Sliwa in order to set up a one-on-one contest between Mamdani and former Gov. Andrew Cuomo. 

Steve Witkoff, a top aide to the president, met with Adams during a recent visit in Florida. 

Just last week, Mr. Trump weighed in on Sliwa, saying he is "not exactly prime time," and took issue with his devotion to cats. 

"He wants cats to be in Gracie Mansion ... The magnificent home of the mayor. It's beautiful. Gracie Mansion to me is like a fabled place if you're in New York," Mr. Trump said. "Now, we don't need to have thousands of cats."

Cuomo has not responded to Trump administration efforts to set up a one-one contest with Mamdani, but he has called Adams a "spoiler" in the race, and said if he were in a one-on-one contest with Mamdani, he would win.