Cynthia Nixon, the Sex and the City actress and activist, declared her challenge against incumbent New York Gov. Andrew Cuomo almost a month ago, and since then she’s managed to shake up what should have been a sleepy Democratic primary race.

Nixon has tried to make it clear she’s not just a celebrity candidate, visiting public housing residents in Brooklyn and meeting with residents upstate in Hoosick Falls about contaminated water. She’s gained significant ground in recent polls, though Cuomo still has a commanding lead.

And Nixon, who’s mounting a progressive challenge against Cuomo, seems to have successfully spooked the governor, already succeeding in pushing him left. Cuomo announced a plan to restore voting rights to 35,000 parolees and helped broker a truce in a years-long standoff between rogue and mainline Democrats in the state Senate.

She’s done this by successfully targeting Cuomo’s vulnerabilities, from the city’s subway crisis to the corruption scandals that have continued to plague Albany, the state’s capital. She’s called out New York’s gross income inequality, advocated for legalizing marijuana, and championed public schools, a longtime pet issue. She hasn’t wasted an opportunity to throw New York’s problems at the governor’s feet, but she’s also slowly beginning to carve out a progressive platform of her own.

As surprising as Nixon’s challenge is, it’s still a long shot. It will be no easy feat to unseat a very powerful governor. But she’s succeeding at putting pressure on Cuomo — which is turning out to be a win for progressives in its own way.

Who is Cynthia Nixon — and what is she running on?

Nixon, a native New Yorker, is probably best known for her role on HBO’s series Sex and the City, where she played lawyer Miranda Hobbes, one of the show’s four central characters. Her acting and artistic credentials (Vulture points out she’s one “O” short of an EGOT) inevitably branded her as a celebrity candidate.

But Nixon has also been an activist around progressive causes for years, particularly for LGBTQ rights (Nixon is bisexual) and public education. She fought for same-sex marriage in New York and other states. She’s raised awareness for breast cancer as a survivor. She is a staunch public school advocate and served as the spokesperson for the Alliance for Quality Education.

She was also a high-profile supporter of New York City Mayor Bill de Blasio, and her wife worked for the mayor’s administration in the Department of Education before recently stepping down.

Nixon’s run for governor had been speculated about for months, but she made it official in March with a political ad that focused on New York’s inequality and the widening gap between the rich and the poor — a message, some pointed out, that sounded like the statewide version of de Blasio’s “tale of two cities” from his first mayoral run.

Nixon, in her first weeks as a gubernatorial candidate, has gone on the attack against Cuomo. Her campaign website questions his Democratic credentials and declares, “New York’s eight years under the Cuomo administration have been an exercise in living with disappointment, dysfunction, and dishonesty.” The site also has a section dubbed #CuomosMTA, the hashtag of choice for many frustrated subway riders. Nixon has continued to make investment in the subway a top campaign issue, touting her own ridership to bolster her case.

Income and racial inequality is another big pillar of her campaign. She has criticized Cuomo for giving tax breaks to the one percent and corporations, and has aligned herself with some well-known community groups. She toured a public housing complex in Brooklyn to meet with residents and hear their complaints about conditions amid a growing scandal over lead and mismanagement within New York City Public Housing Authority. Nixon also went to Hoosick Falls in upstate New York, where residents are dealing with a water contamination crisis. The town, close to the Vermont border, is bringing Nixon exposure beyond the city.

She’s also pushing hard for the legalization of marijuana in New York, and recommitted to the issues she’s advocated for years, including LGBTQ and women’s rights and adequate funding for public education.

Why Cuomo’s liberal credentials get questioned

Cuomo, a two-term incumbent with potential political ambitions beyond the governorship, is a skilled operator hailing from one of New York’s most famous political families. He has a deep war chest for his reelection campaign. He rarely avoids an opportunity to criticize President Trump. He’s also championed liberal policies, particularly in his second term, such as paid family leave and a $15 minimum wage.

But Cuomo is still perceived as being somewhat vulnerable from the left, as his brand of transactional politics sometimes feels out of place in an era of growing Democratic activism.

Nixon’s campaign has painted the governor as a centrist and Albany insider, whose policies have favored corporations and the rich at the expense of struggling New Yorkers. And this attack has succeeded, in the month since she’s been a candidate, in pushing the governor toward the left, making him appear even more eager to notch some progressive accomplishments.

After campaigning as a centrist in 2010, Cuomo championed socially liberal policies — New York legalized same-sex marriage in 2011, for example — but embraced a more fiscally conservative agenda, opposing tax increases and cozying up to business interests. He also didn’t make nice with some public sector unions, particularly teachers unions, and in 2014, he faced an unsuccessful but still surprising challenge from activist and professor Zephyr Teachout in the Democratic primary.

Cuomo heaped up some solid progressive accomplishments even before Nixon challenged him for his job. He championed a $15 minimum wage and enacted a 12-week paid family leave policy; got strict gun control into law; introduced a free (though imperfect) college tuition program for certain students; banned fracking; allocated $10 million for a defense fund for immigrants facing deportation; and raised the age for juvenile offenders to 18.

Yet liberals often don’t give Cuomo credit. He has a reputation as a political animal rather than a real populist — an ambitious, skilled operator. Michael Shnayerson, who wrote a 2015 Cuomo biography, told the New York Times in 2017 that though Cuomo has one of the best résumés of any recent Democratic figure, his political style can come off as “a dark, Nixonian character, harsh and vindictive.”

Another longtime sticking point was the balance of power in the state Senate. A group of Democrats known as the Independent Democratic Conference caucus with the Republicans, effectively keeping the state Senate in GOP hands. (Democrats had a majority in name in 2012 and 2016.) Cuomo’s critics argued he hasn’t done enough to force the rogue Democrats back into the fold or put real effort behind trying to unseat them.

But in April, after seven years, Cuomo brokered a deal — allegedly over cookies and coffee at a Manhattan steakhouse — to dissolve the IDC and bring most of the Democrats back into the fold. “Today what unites us is more important than what divides us,” he said at a press conference after the deal.

A unified party and a special election on April 24 could finally tip the balance of power back into Democrats’ hands.

Still, Cuomo isn’t exactly getting credit for being some master dealmaker. As one Cuomo insider told New York magazine’s Jessica Pressler in a Nixon cover story, if Cuomo could get this done over cookies and coffee, “Why the fuck didn’t you do it before?”

New York City: land of mayoral feuds and subway meltdowns

Nixon isn’t just challenging Cuomo from the left. She’s focusing on a key issue that residents of New York City are fuming over, and she’s doing it as an ally of New York’s other most prominent Democrat, Bill de Blasio. Nixon was an early and outspoken de Blasio supporter and worked on his transition team after his first victory. Two of de Blasio’s former aides are working on Nixon’s campaign.

Cuomo and de Blasio have a personal animosity that spills over into politics. Their bickering sometimes borders on the ridiculous — see the saga of the Harlem deer — but it underscores a broader problem: The mayor and the governor need to work together on policies from affordable housing to homelessness to education, and their attempts to undercut each other create a frustrating gridlock.

This has been especially acute when it comes to the subway system, which is overcrowded, underfunded, and slapped together with outdated technology and aged infrastructure. The governor and the mayor blame each other for the crisis.

Cuomo is technically in charge. The Metropolitan Transportation Authority, which oversees the subways, buses, and commuter rails, is a state-run agency. But as the subway hit a crisis point last summer, the governor deflected. He eventually declared a state of emergency and the MTA came up with an $800 million turnaround plan, but Cuomo and his MTA chair feuded for months with de Blasio over the cost. The city agreed to fork over half in April, but in the meantime, the subways continued to spiral into disarray.

Nixon is capitalizing on the subway’s disrepair and the depths of rider despair. In her campaign ad, she notes that “unlike Gov. Cuomo, Cynthia Nixon rides the subway every day.” Nixon said on her website that she’d prioritize emergency rescue, though she hasn’t outlined the specifics, particularly when it comes to revenue raising. But her campaign has been trying to capitalize on the optics. Her staffer tweeted a photo of her on the subway the week of her campaign announcement — with her train out of service:

Nixon tries to paint Cuomo as part of the swamp

Nixon is also targeting a vulnerability of Cuomo’s beyond the subway’s limits: the corruption in Albany. “If Washington is a swamp, Albany is a cesspool,” Nixon said at a campaign event in March. The implication, of course, is that Cuomo is mired in the muck.

Cuomo ran in 2010 on a promise to clean up Albany, and he passed modest ethics reform in 2011. He’s proposed other ethics reforms — banning state lawmakers from taking outside income, for example — but these proposals tend to die once they hit the state legislature. Critics bemoan the lack of pushback.

And a corruption scandal unfolded uncomfortably close to Cuomo. In March, Cuomo’s top aide, Joseph Percoco, was convicted on federal corruption charges for taking more than $300,000 from people who had business with the state.

Cuomo wasn’t implicated in any wrongdoing, but it’s a stunning blow nonetheless. Percoco wasn’t some lackey; he was known as Cuomo’s enforcer, and the governor has called him “my father’s [former Gov. Mario Cuomo] third son.” The governor described the verdict as “personally painful” and suggested putting in additional ethics safeguards.

Cuomo might have 2020 on his mind

Nixon could do some damage to Cuomo if he wants to join the long list of 2020 Democratic hopefuls. He has steadily been building up his résumé and bolstering his anti-Trump credentials. He’s even sounded a bit more like a presidential candidate of late. But even if he survives, a tough primary could leave him weakened on the national stage — especially if it becomes a test of his liberal bona fides.

Cuomo initially joked about Nixon’s run before she officially declared, seeming to write her off as another celebrity candidate. “If it was just about name recognition, then I’m hoping that Brad Pitt and Angelina Jolie and Billy Joel don’t get into the race because if it was just about name recognition, that would really be a problem,” he said.

But Cuomo later changed his tune. The day Nixon actually announced her candidacy, he released a statement that put front and center his liberal accomplishments, which read like a progressive wish list: “Governor Cuomo has delivered more real progressive wins than any other Democrat in the country, including passing marriage equality, the strongest gun safety law in the nation, a $15 minimum wage, free college tuition, paid family leave, record setting funding for public education, expanding and protecting healthcare for our most vulnerable, and banning fracking.”

And he has tried to keep building on that list in the month since Nixon’s profile has grown. The governor found a way to bring Democrats back into the fold, setting him up for the potential of full Democratic control of government.

Cuomo got legislation passed that takes firearms away from domestic abusers. He announced this week that, by executive action, he will attempt to restore voting rights to as many 35,000 parolees. He’s declared a state of emergency within the city’s public housing and appointed an independent monitor to oversee repairs.

Cuomo, who had been resistant to legalizing weed (though he did appoint a commission to study it earlier this year), indicated at a press conference he is anything but: “It is no longer a question of legal or illegal. It’s legal in Massachusetts. It may be legal in New Jersey,” he said. “Which means for all intents and purposes it’s going to be here anyway.”

Nixon has clearly put Cuomo on the defensive. And there are signs that she’s chipping away at his formidable lead. A Sienna College poll taken before her official announcement had her trailing Cuomo 66 to 19 percent among Democrats. In the latest poll from Sienna College, Nixon cut into Cuomo’s lead by 16 points, now trailing 58 to 27 percent.

How Nixon’s candidacy will play upstate or in the suburbs, where issues like the subway matter but perhaps don’t feature as heavily, is also an open question. But it appears she’s making some inroads among upstate voters — better than in the city, in fact — where Cuomo leads by only 11 points, 48 to 37, according to the Sienna College poll.

Yet Cuomo has built-in advantages: allies, name recognition, reserves to the tune of $30 million. He’s also got the backing of some powerful unions. The Working Families Party, a small but influential progressive party with union support that Cuomo worked hard to woo in 2014, endorsed Nixon — but several union groups split in protest, dampening her victory.

New York’s Democratic politicians are also lining up behind him. Sen. Kirsten Gillibrand officially endorsed Cuomo last month. Rep. Sean Patrick Maloney referred to Nixon’s bid as “a wasteful, negative, time-consuming exercise.”

But Nixon’s candidacy has resonated. Her anger over the subways has found a receptive audience. And according to her campaign, she raised more small-dollar donations — meaning less than $200 — in her first day as a candidate than Cuomo had raised since 2011.

But a lot can happen between now and September. Nixon’s campaign might be a victory for liberal Democrats if she manages to keep pushing Cuomo further and further left. With the renegade Democrats back in the fold, Cuomo has an even greater chance to rack up some extra liberal accomplishments.

The question is less about 2018 than 2020. Cuomo can likely defeat Nixon, but a close or contentious race in New York might leave him too battered for a presidential primary.