Who is Cori Bush, the nurse, pastor and activist who ended a 52-year political dynasty?

A protest leader and activist who once spent months living out of her car after being evicted from her home, won a stunning upset in Missouri's Democratic primary Tuesday in the race for a House seat that has been held by the incumbent's family since the Nixon administration.

Cori Bush defeated Rep. William Lacy Clay Jr. by about 3 percentage points to become the Democratic candidate for Missouri's 1st Congressional District. Clay has held the seat since 2001 after succeeding his father, former Rep. William Lacy Clay Sr., who was elected in 1968.

A nurse, pastor and single-mother, Bush, 44, became a prominent voice in the protests that followed the fatal police shooting of Michael Brown, an unarmed Black 18-year-old, in Ferguson, Missouri, in 2014. She continued to be a powerful voice against police brutality and racial discrimination, issues that exploded back to the forefront of the American consciousness with the death of George Floyd at the hands of Minneapolis police in an incident captured on a video.

"It is historic that this year, of all years, we're sending a Black, working-class, single-mother, who has been fighting for Black lives since Ferguson all the way to the halls of Congress," Bush said Tuesday after her win. A survivor of COVID-19, Bush and her supporters wore masks as she delivered her remarks.

"They counted us out," she said. "I’m just the protester, I’m just the activist with no name, no title and no real money. That’s all they said that I was. But St. Louis showed up today."

Bush strongly supports the movement to "defund the police" and said she will passionately advocate for that policy if she is elected to the House. On CNN Wednesday, she vowed to apply "the same energy that I put in on the streets of Ferguson for more than 400 days while we were out there" and "the same energy that I had fighting on the streets for justice for George Floyd and Breonna Taylor" to "make sure that defund is first understood, and that we bring that home to our community, because our children's lives depend on that."

Bush is a progressive whose politics make her a likely ally for Democrats such as Rep. Alexandria Ocasio-Cortez, D-N.Y., and Sen. Bernie Sanders, I-Vt.

"She is a true progressive who stands with working people and will take on the corporate elites of this country when she gets to Congress," Sanders, who endorsed Bush in January, said in a tweet congratulating her on her victory.

Bush campaigned for Sanders in the Democratic primary, but she said she will be working to help former Vice President Joe Biden defeat President Donald Trump in November, despite Biden's opposition to defunding the police.

"We can't continue with Donald Trump," she told CNN. "We cannot live under a Trump administration. So, we can disagree on an issue, but that won't stop me from fighting to have a Democrat in that seat."

Bush lost a primary bid against Clay in 2018. Ocasio-Cortez strongly backed her that year, but did not endorse her this time against Clay, who announced his support for the first-term congresswoman's Green New Deal in a statement that included a photo of himself standing closely beside her.

Clay ran on his decadeslong record in Congress.

"This election is a simple choice," Clay said in a Monday statement. "Cori Bush’s Empty Rhetoric, or my record of real results and real reforms for the people."

Bush is almost certain to win the general election against the Republican primary winner, actor and comedian Anthony Rogers. A Republican has not held the seat since 1949 and the Cook Political Report ranks it one of the most Democratic districts.

Contributing: The Associated Press

This article originally appeared on USA TODAY: Cori Bush: Ferguson activist upsets Rep. William Lacy Clay in Missouri