When Kayla Reed started using the phrase “Bye, Bob” on social media over the summer, no one fully understood what a powerful message for tens of thousands of voters, and supporters of criminal justice reform, it would become. But on Tuesday, voters and activists like Reed in St. Louis County, Missouri, pulled off a historic win, booting out Bob McCulloch, the St. Louis County prosecutor who failed to bring charges in the police killing of Michael Brown. It was an office McCulloch had held for 28 years.

“I’m 28 years old, that’s my entire life, under one prosecutor,” said Reed, who heads Action St. Louis, a grassroots political organizing group founded after the Aug. 9, 2014, killing of Brown.