AMNA NAWAZ: In a stunning upset, 33-year-old Zohran Mamdani won last night's Democratic primary for New York City mayor.

Final results won't be official for several days, but his win has sent shockwaves through the Democratic Party.

Mamdani spoke to supporters late last night.

ZOHRAN MAMDANI (D), New York City Mayoral Candidate: If this campaign has demonstrated anything to the world,it is that our dreams can become reality.

(CHEERING) ZOHRAN MAMDANI: Dreaming demands hope.

And when I think of hope, I think of the unprecedented coalition of New Yorkers that we have built... (CHEERING) ZOHRAN MAMDANI: ... for this, this is not my victory.

This is ours.

(CHEERING) AMNA NAWAZ: For more on his win and what comes next, we're joined by Errol Louis.

He's political anchor for Spectrum News NY1 and host of the "Inside City Hall" program.

Errol, welcome back to the "News Hour."

Good to see you.

ERROL LOUIS, Spectrum News NY1: Great to be with you.

AMNA NAWAZ: So this is being called a New York City miracle, a political earthquake.

Mamdani went from being a little-known state assemblyman to taking down the former New York Governor Andrew Cuomo.

How did he do it?

ERROL LOUIS: Well, that's what we're all trying to figure out today, but the short answer is that he represented a new generation.

He's less than half the age of Andrew Cuomo.

He's a relative newcomer who has a lot of newcomer's problems, meaning it's hard to pay the rent in New York City.

It's hard to get the cost of living under control.

And he proposed some very basic, very straightforward solutions that a lot of people really like.

AMNA NAWAZ: He is a self-described Democratic socialist, we should say.

And some of the specific promises that he ran on include a rent freeze, free city buses, raising taxes on the wealthy.

If he wins, Errol, are those achievable or are they just aspirational?

ERROL LOUIS: Some are easily achievable.

When they say a rent freeze, what they mean is that there are about a million apartments in New York that are under tightly regulated control by something called the Rent Guidelines Board, and the mayor makes all of the appointments to the board, so he could influence the board sufficiently to get a rent freeze over the course of a year or two.

That, he can do.

Almost everything else, he'd have to go back to his friends in the state legislature.

He'd have to ask for help from the governor.

That help is not necessarily forthcoming, by the way.

If he wants to raise taxes and do some other expensive stuff, it's going to have to be a joint project.

AMNA NAWAZ: So, when you look at how he won, he referenced in the sound bite we just heard, the coalition that got him here.

It's even more striking when you look at the map.

He was able to win in progressive parts of Brooklyn, in working-class parts of Queens, in affluent parts of Manhattan.

How significant a redrawing of the map is this?

ERROL LOUIS: Well, the question is whether or not we're seeing a complete realignment.

The reality is, though, he really is taking advantage of some underlying demographic trends that all New York politicians are going to have to at least recognize.

For example, he himself is part of a fast-growing South Asian community.

There are a lot of people here from India, from Pakistan, from throughout the Indian diaspora.

That includes Guyana.

These are people who want to see themselves reflected in government and in leadership.

There are 750-plus-thousand Muslims in New York City.

He spent -- apparently, last week, his campaign says he went to 135 mosques.

There are going to be some new ways that politics is done in New York, because Zohran Mamdani is proving that if you tap into these newer communities and you speak to people's needs, they will reward you at the polls.

AMNA NAWAZ: And obviously it's gotten a lot of national attention.

What are you seeing in terms of the Democratic Party across the country and what kind of lessons they're taking away from this win?

ERROL LOUIS: Well, there's an active discussion going on all over social media.

What I can tell you is that some heavy hitters, Senator Chuck Schumer, Hakeem Jeffries, the Democratic leader in the House, have all signed up on the dotted line.

They have all congratulated him.

They recognize talent when they see it, political talent.

And they recognize political movement when they see it.

There's a lot of youthful energy that was turned into votes.

We have seen a lot of youthful energy in the past.

It's not always turned into voting power.

And politicians understand that above all else.

So I think Democrats around the country are going to look and see is if this could be set next to the win of Michelle Wu up in Boston just a couple of years ago as part of the new generation of 30-something Democrats -- Alexandria Ocasio-Cortez, who endorsed Zohran Mamdani, would certainly fall at that category -- who are going to be the future of the party.

AMNA NAWAZ: Errol, we have also seen some pretty ugly attacks awakened in reaction to Mamdani's win.

That includes attacks on his faith.

He would be the city's first Muslim mayor if he's elected.

And we have seen some Islamophobic like this one from the prominent MAGA voice Charlie Kirk.

He wrote: "Twenty-four years ago, a group of Muslims killed 2,753 people on 9/11.

Now a Muslim socialist is on pace to run New York City."

What does all of this mean for the kind of campaign you could see ahead?

ERROL LOUIS: Well, look, hatred and division don't work.

There were ads that fell only slightly short of that ugliness you just read that were paid for and projected by millions of dollars in this last campaign.

And Democrats, at least in New York City, kind of shrugged and moved on.

That -- look, people only resort to those kind of tactics when they're afraid.

And people get afraid because they realize that the world is changing right in front of them and they don't know how to react.

That's really what this election has been about.

And I think that's what the next cycle is going to look like between now and the next presidential race.

AMNA NAWAZ: Errol Lewis, political anchor for Spectrum News NY1, thank you so much for joining us.

Always great to talk to you.

ERROL LOUIS: Glad to be here.