Anthony Scott honours the memory of his brother Walter each time he casts a ballot.

“I’m not the sort of person to go and visit graves,” he said, sat at a bustling diner on the outskirts of Charleston. “I can memorialize better by making sure people never forget. Weighing up my vote, making sure the right person is put in the right place.”

Walter Scott’s fatal encounter with a white North Charleston police officer gripped the national and international news agenda in 2015 as the most powerful example of the fatal consequences of racially biased policing. The incident was captured on video by a witness, which showed Scott running away as he was shot five times in the back by officer Michael Slager, who is now serving a 20 year federal prison sentence following a rare conviction against a police officer caught using excessive force.

The case also propelled Scott’s family into the national conversation about race and policing, which dominated the final years of the Obama administration before mostly shrinking away from mainstream discourse as Donald Trump entered office in 2016.

But as the fifth anniversary of the shooting approaches in April, Anthony and others associated with the case hope the South Carolina primary on Saturday will serve as a reminder of the truths it unveiled, and thrust police and criminal justice reform into the spotlight again on the 2020 ballot.

Anthony had not yet decided who he would vote for on Saturday. “It could come down to a prayer before I pull the lever,” he said.

But his choices were narrowed to two candidates: former vice-president Joe Biden, who is now projected to win here, and the billionaire hedge fund manager Tom Steyer, who has invested millions in the state and is currently polling in third place.

Both men, however, have their own problematic histories on the issue of criminal justice. Biden, a former US senator from Delaware, was instrumental in the passing of the expansive 1994 crime bill, which mandated tougher federal sentencing guidelines and funded more state prisons. While Steyer once invested in Corrections Corp of America, one of the country’s largest private prison companies.

Biden has defended his role in the legislation, a multifaceted bill that also included more resources to target violence against women and measures encouraging states to treat drug addicts rather than incarcerate them.

Steyer, on the other hand, points to the fact he divested from Corrections Corp in 2006 and now, along with all the other Democratic candidates, supports abolishing federal government use of private prisons.

In a brief interview with the Guardian, the candidate did not provide specifics on how he would end their use in high incarcerations states in the deep south like South Carolina. “I came to the conclusion [we should end their use], I made the right decision, and I’ve been working on it ever since,” he said.

Anthony Scott, like many other Democratic voters in South Carolina where criminal justice reform remains a top voting priority, was unfazed by his preferred candidates’ prior history.

The same could not be said for the Scott family’s attorney, Justin Bamberg.

In 2015, Bamberg, who also serves as a state representative, became one of the public faces of the Walter Scott shooting. He often spoke on behalf of family members who were too grief stricken to talk in public.

In 2016 the attorney and civil rights campaigner initially endorsed Hillary Clinton before switching his allegiance to Bernie Sanders, who lost South Carolina comprehensively four years ago.

Sanders is currently polling second here, a result Bamberg says is partially attributable to the Vermont senator’s long time commitment to civil rights and criminal justice reform.

Bamberg said he began backing Sanders after reading his 1998 autobiography “Outsider in the House”, documenting his involvement in the civil rights movement in Illinois, where he was arrested fighting university housing segregation in 1963.

“Those were his qualities back then, and that’s what they are still today,” Bamberg said in a phone interview.

The attorney pointed to both Biden and Steyer for their prior record on the issue. But he reserved particular criticism for former New York City Mayor Mike Bloomberg and his administration’s implementation of Stop and Frisk policing in New York City, a policy that disproportionately targeted people of colour and was eventually ended by a court judgement that declared it unconstitutional.

The Scott incident itself was triggered by an iteration of the same sort of policing. The 50-year-old unarmed African American was pulled over by Slager for a busted vehicle tail light before he fled on foot.

It was revealed during civil litigation that the North Charleston police department had quietly implemented a ticket quota system for its officers, which lawyers argued disproportionately affected black residents.

The policy has since been outlawed by reforms in the wake of Scott’s death, following legislative action by Bamberg and other state representatives who have also endorsed Sanders.

“People like me who passionately fight for this stuff wouldn’t be endorsing Bernie if he weren’t sincere and fighting for it too,” Bamberg said.

Despite their differences over the best Democratic candidate to vote for – both were united in their criticism of the Trump administration, which has rolled back a number of the federal provisions designed to reign in racially biased police departments implemented under Obama.

“Whatever progress we had been making has gone out of the door,” said Anthony Scott.

Bamberg said he had rarely discussed the Democratic race with his clients.

“Having seen grown men broken down in tears as they bury their brother, their son … you don’t get into politics.”

But, he urged all those running to honour the legacy of the case.

“It is important, for both citizens and for anyone who wants to be in a position of leadership not to forget what the shooting of Walter Scott did, not just for South Carolina but for this entire country.”