ARI SHAPIRO, HOST:

It's the last week of primaries before November's midterm elections. Progressive candidates have scored big upsets recently over candidates from the Democratic Party establishment, and they'll try to do that again this week with primaries in New Hampshire, Rhode Island and New York.

There's a primary there for governor that has gotten a lot of attention. It's between the current governor, Andrew Cuomo, and Cynthia Nixon, an education activist and actress best-known for her role in the show "Sex And The City." We'll hear from Nixon in a few minutes.

First, NPR lead political editor Domenico Montanaro's here to catch us up on how these primary battles have been fought. Hi, Domenico.

DOMENICO MONTANARO, BYLINE: Hey there, Ari.

SHAPIRO: How significant is it that progressives have scored these big victories, sometimes catching incumbents by surprise?

MONTANARO: Well, so far in this campaign, there've been some high-profile progressive wins, like with Andrew Gillum for governor of Florida, for example, and for the House, where you had two relatively unknown candidates go and knock off Democratic incumbents in Alexandria Ocasio-Cortez in New York and Ayanna Pressley in Massachusetts, who is pretty well-known in Boston, but outside of that, not as much.

Overall though, the Brookings Institution's been keeping track of how progressive versus establishment candidates have been doing. By the numbers, progressive candidates have emerged in only about a quarter of all the races, and in many of those, have actually been in Republican-leaning districts. So the likelihood that they'll change the makeup of Congress on the Democratic side isn't very high at this point.

Mostly, we're going to see this continue when and if Democrats at some point take back Congress, and especially in that 2020 primary race.

SHAPIRO: The race in New York, of course, is for governor. We're not talking about Congress. But how does that race compare with some of the other contests we've seen?

MONTANARO: I mean, there's lots of similarities. I mean, Nixon is pushing things, for example, on the issues that are certainly more liberal than Andrew Cuomo, the governor - current governor has been willing to go, like, for example, on raising taxes on the wealthy to fund schools, wanting statewide universal health care, whether public sector unions should have the right to strike, for example. You know, she also represents a wave of women, minorities and LGBTQ candidates who are running. Nixon identifies as queer.

But it's also different in a lot of other ways, too. You know, Cuomo - the name Cuomo is political - Democratic political gold in New York state. His father was governor. He's got ties and connections to lots of high-profile Democrats because of that, including Joe Biden, who has been all over the airwaves for Cuomo, and Hillary Clinton, who campaigned with him this past weekend.

Cuomo's also seen this challenge coming. He spent $8 million just in the last three weeks, despite the fact that he's up by big poll numbers. You know, for context, Nixon has only spent about 450,000 in the last three weeks.

SHAPIRO: Wow.

MONTANARO: That's roughly equivalent to what Cuomo spent per day.

SHAPIRO: Wow. When you take a step back, do you see these progressive candidates shaping the Democratic Party heading into the November midterms, and potentially even into the 2020 presidential race?

MONTANARO: Well, in many ways, progressives have already won. I mean, they've been able to shift Democratic talking points and politics toward things like “Medicare-for-all,” $15 minimum wage, and for some, Abolish ICE, which, you know, a lot of moderate Democrats and establishment Democrats don't particularly like.

But a lot of this is going to be on the stage in the 2020 primaries for absolute certain. We're seeing almost a mirror image of what played out with the Tea Party. And I think it's going to really be a big factor in those primaries in 2019.

SHAPIRO: That's NPR's Domenico Montanaro. And you can also hear him on the NPR Politics podcast. Thanks, Domenico.

MONTANARO: You're welcome. Transcript provided by NPR, Copyright NPR.