ST. LOUIS (AP) — Few members of Congress are more entrenched than William Lacy Clay of St. Louis, but a once-homeless woman spurred to activism in Ferguson believes she could be the next Democrat to pull off a big primary upset.

Cori Bush watched in June as her friend, democratic socialist Alexandria Ocasio-Cortez, shocked the political establishment by beating 10-term Rep. Joseph Crowley in the New York Democratic primary. That has fueled Bush's optimism heading into Missouri's Aug. 7 primary.

"I actually feel like we have the momentum," said Bush, 42. "I believe that we have what we need to be successful."

It won't be easy, even with strong support from Ocasio-Cortez. Missouri's 1st Congressional District has been represented by Clay or his father for a half-century. Bill Clay served 32 years before retiring in 2000. William Lacy Clay, 62, was elected that year and has never been seriously challenged since. Both Clay and Bush are black, and blacks slightly outnumber whites in the district that includes St. Louis and north St. Louis County.

Clay is confident but campaigning "vigorously."

"I'm a progressive and I champion jobs, health care, housing, protecting the right to vote, standing up to defend the 1st Amendment and opposing Donald Trump's terrible assault on our democracy," Clay said. "So I'm not ashamed of my record, I'm proud of it, and over the years the voters in this district have agreed with the direction I take to be their voice in Congress."

Bush has faced big challenges before, including a period of homelessness. She became ill while pregnant with her second child in 2001 and had to quit her job at a preschool. When she and her then-husband were evicted from a rental home, the couple, their newborn and 14-month-old son lived out of a Ford Explorer for several months.

Eventually, the couple divorced. Bush earned a nursing degree. She also became a pastor.

Michael Brown's death in 2014 in Ferguson vaulted her into another role: activist. She became a leader of some of the many protests that followed the fatal police shooting of the black, unarmed 18-year-old. She was back on the streets last fall, after a white St. Louis officer was acquitted in the shooting death of a black suspect.

"I am a very vocal, on-the-ground fighter, an advocate," Bush said. "I'm someone that touches the community with her feet on the ground."

Experts say Bush faces long odds. University of Missouri-St. Louis political scientist Terry Jones said Clay may have a relatively low national profile, but that doesn't matter to his constituents.

"He knows he has the backing of the majority of that base," Jones said.

But Bush is getting strong support from Ocasio-Cortez, the star of the emerging democratic socialist movement who has been campaigning for like-minded candidates across the country.

Her appearance in St. Louis last month on behalf of Bush, though, was personal. The two met last year at a summit for potential Democratic challengers.

"We bonded," Bush said. "The first time she opened her mouth I felt she was really fierce. Since then we've always kept in contact."

In fact, Bush offered a pep talk to a nervous Ocasio-Cortez during a video chat on the day of the New York primary. Ocasio-Cortez, 28, was outspent 18-1 and polls gave her no chance. Bush sensed an upset on election night.

"I had the television on and I was looking at my phone and when I saw she won I cried, I cried like a baby for hours," Bush said. "It wasn't just about her. It was about anybody that's the underdog in their race."

Ocasio-Cortez urged support for Bush in her victory speech and on Twitter. The response was swift.

In the days before Ocasio-Cortez's victory, Bush was getting about $9 a day in contributions (she doesn't accept corporate donations), she said.

"Immediately all of my social platforms blew up," she said. "Between 9:30 and midnight we probably received $2,000 in donations. The next 24 hours it was like $8,000."

Ocasio-Cortez gave another boost to Bush on July 21 when she spent the day in St. Louis campaigning on her behalf. She called Bush "one of the most inspiring people I've ever met in my life."

___

Sign up for "Politics in Focus," a weekly newsletter showcasing the AP's best political reporting from around the country leading up to the midterm elections: https://bit.ly/2ICEr3D