Alexandria Ocasio-Cortez’s shocking primary victory in New York over House Democratic Caucus Chairman Joseph Crowley raised the question: Who could be the next incumbent Democrat to go down? Ocasio-Cortez and her allies are hoping it will be Missouri Rep. William Lacy Clay. 

Four Democrats, including Clay, will be on the primary ballot Tuesday for the St. Louis-based 1st District, but the nine-term congressman’s biggest threat comes from nurse and activist Cori Bush. Ocasio-Cortez traveled to St. Louis to campaign with Bush, who casts herself as part of a new generation of bold progressive leaders. 

Clay has faced primary threats before, but some Democrats think this will be his closest race yet. Still, they were confident Clay would win.

“I do think that Ocasio-Cortez emboldened all challengers to sitting established Democrats across the country,” said former Missouri state Rep. Don Calloway, who previously represented the St. Louis area and is backing Clay.

Calloway warned against applying the New York primary example to other contests. He noted that the demographics in Crowley’s district had shifted underneath the longtime lawmaker and suggested Crowley was asleep at the wheel and didn’t recognize Ocasio-Cortez as a threat.

“That is simply not the case in Missouri 1,” Calloway said.

Watch: Which Incumbents Could Follow in Crowley’s Footsteps?

Closest race yet?

Public polling is scarce for this safe Democratic seat, but Calloway and one other veteran Missouri Democratic operative predicted this would be tightest primary of Clay’s House career. 

He survived a 2016 intraparty contest after the protests in Ferguson energized activists in the area and raised questions about whether he could withstand a challenge. He won by 36 points. Four years earlier, he defeated fellow Democratic Rep. Russ Carnahan in a 2012 primary by 29 points, in a battle between the scions of two iconic political families.  

But this year could be different because of the energy bolstering progressives across the country.

Bush is running a race similar to Ocasio-Cortez: saying she would be a bolder fighter for the district; arguing that, as a nurse and activist who was once homeless, she better understands voters’ struggles; and promising that she is not beholden to special interests because she rejects corporate PAC money.

Bush argues she also has a real chance of defeating Clay because she was already known in the district before she decided to run. She helped organize protests in Ferguson after a police officer shot and killed unarmed 18-year-old Michael Brown. Bush ran unsuccessfully for Senate in 2016, garnering more than 42,000 votes despite not having much paid media beyond 150 yard signs.

“They know that I show up. They know that I’m in the community,” she said in a phone interview Friday. “I didn’t just come from out of nowhere and decide to run for Congress.”

Bush did benefit from increased donations, volunteers and media attention following Ocasio-Cortez’s victory in June. The New York Democrat traveled to St. Louis late last month to campaign for Bush. The pair have been friends since meeting last year at a summit for Brand New Congress, a group formed by former staffers of Sen. Bernie Sanders’ presidential campaign. Nina Turner of Our Revolution, another group launched by Sanders staffers, campaigned with Bush on Saturday.

But some Democrats cautioned that Ocasio-Cortez’s success might not be easy to replicate against Clay.

Clay outspent Bush by nearly five times in the pre-primary reporting period between July 1 and July 18, spending $106,000 to Bush’s $22,000.

Clay’s campaign did not respond to requests for comment, but the congressman recently appeared confident in an interview with St. Louis Public Radio.

“I started my congressional career in a contested primary with five opponents and came out of that successfully. And I was able to do that because I ran on a record,” Clay said. “And unlike anyone else in this race … I do have a record to run on.”

The incumbent has a well-oiled turnout machine, coupled with name recognition that goes back decades to when his father William L. Clay served in Congress. The elder Clay was a co-founder of the Congressional Black Caucus.

“Ultimately, Congressman Clay’s operation is so well-aged. It produces well and he can flip the switch and drive voters out,” said Brian Wahby, former Democratic Party chairman for the city of St. Louis. “So I think that will ultimately be the difference.”

Broader divisions

Calloway, the former state lawmaker, commended Bush for running a positive campaign and said she is well-liked among Democrats.

He also said primaries are ultimately good for the party, but the race in the 1st District did reflect a sentiment, particularly among younger Democrats, that seniority isn’t always a good thing. 

“For better or for worse, there is a feeling among many of the younger far left of the party that tenure automatically makes one out of touch,” Calloway said.

The competitive primary has highlighted other divisions among Democrats that boiled over during the 2016 presidential primary and have persisted into the 2018 cycle.

The progressive group Democracy for America has endorsed Bush (they also endorsed Clay’s primary challenger in 2016) and believes she has a real shot at winning even though Clay easily won two years ago.

Bush is benefitting from “a real hunger for new leadership putting forward big bold ideas,” group spokesman Neil Sroka said.

And her supporters say it’s just the beginning for upstart challengers looking to take on longtime incumbents.

Corbin Trent, a spokesman for Ocasio-Cortez and the co-director of Justice Democrats, said the movement to push the party to the left would persist, especially as challengers do well. Justice Democrats backed both Ocasio-Cortez and Bush.

“Like anything else … once you show that something’s possible, the next time you do it, it becomes easier,” Trent said. “This is a long-term project.”

Bush also said her victory Tuesday would inspire others to wage primary campaigns in future cycles. And Bush, Sroka and Trent all agreed the movement would not be deflated if she loses.

“What Alexandria Ocasio-Cortez’s victory showed us is that there is a pathway to victory for people who are fighting for bold, inclusive populist reform and hunger for a next generation of young women of color,” said Sroka.

“And I don’t think that goes away, regardless of what happens on Tuesday,” he said.