Four years ago this month, 18-year old Michael Brown was brutally killed by a white police officer in St. Louis County—in Ferguson, to be precise. Since then, and thanks to black activists, there has been a growing and powerful awareness that Brown’s death was not an aberration. It was and remains a symptom of a criminal justice system that promotes mass incarceration and even encourages violence and injustice against black and brown people.

Nationally, 80 percent of races to elect a prosecuting attorney go uncontested. This Tuesday, St. Louis County will buck that trend. Voters will head to the polls to register just how fed up they are with a criminal justice system that has failed them. And for the first time in a long time, one of the chief caretakers of that system, Robert McCulloch, the man who let Brown’s killer go free, will face a serious reform-minded challenger. That challenger is Wesley Bell.

Since 1991, McCulloch has served as St. Louis County’s prosecuting attorney. He was reelected to a sixth term in 2014 with over 95 percent of the vote—just five days before Brown was killed. In the 27 years McCulloch has held office he’s overseen a system that has incarcerated black people at a staggering rate. Blacks make up one-fourth of the county’s population, but two-thirds of those who are locked up.

Few public officials have as much power over our everyday lives as a local prosecutor. He decides who gets prosecuted, and for what crimes. He chooses what to do with evidence collected from dragnet practices like stop-and-frisk that overwhelmingly target people of color. He decides whether to tacitly approve of police misconduct, or to hold officers accountable when they violate the law.

In an election cycle unlike any we have seen in recent memory, groups like Color of Change PAC, Faith in Action, People’s Action, the Real Justice PAC and Black Struggle in St. Louis are mobilizing black voters to show up and vote for county prosecutor all across the country. Why? Because our goal is to hold prosecuting attorneys accountable when they act as tools of an unjust and racist criminal justice system. We are done with seeing so many elected prosecutors defend a deeply racist system. We want them replaced with reformers.

Historically, political races for these offices have been dominated by the candidate who looks tougher on crime. But there’s ample evidence that new voices and leaders can win at the local level. Chicago’s Kim Foxx and Philadelphia’s Larry Krasner both won crowded races for district attorney while championing reform, and both have made real changes to the system since taking office.

There have been too many broken promises, killings and racist acts that have gone unanswered by the nation’s justice system. By acting on the local level, we have an opportunity to vote into office candidates who can quite literally make the difference between life and death.

When we say that the political calculus on mass incarceration and police violence is changing, make no mistake: It’s changing because the movement is making it change.

In St. Louis County and throughout the nation, Michael Brown’s death and the demonstrations that followed represented a turning point in our nation. It galvanized a new generation of action and activists. It illuminated the deep need for our community to build and wield power—electoral power. It brought the Black Lives Matter movement to the wider American consciousness, and demonstrated to the whole country the inherent viciousness of a society that continues to treat as unequal its black and brown citizens.

We’ll soon see whether voters in St. Louis County are able to hold accountable a law enforcement “leader” who prevented justice after the killing of one of his constituents. But no matter the outcome, this election for prosecutor has been different than what’s come before. Let’s hope the rest of the nation is paying attention.

Rashad Robinson is the spokesperson for Color of Change PAC, the political action committee of the nation’s largest online racial justice organization.