Last August, Wesley Bell trounced longtime St. Louis County prosecutor Bob McCulloch in the Democratic primary. Bell won with 57 percent of the vote. Since he had no challengers from other parties for the general election, Bell is set to take office next month. He’ll be the first black county prosecutor St. Louis County has ever had. McCulloch held the office for 28 years, including being at the center of national controversy over his handling of the 2014 shooting of Michael Brown by Officer Darren Wilson.

Perhaps appropriately, Bell happens to be a city councilman in Ferguson, the scene of Brown’s shooting and the subsequent protests, violence and police crackdown. Interestingly, like McCulloch, Bell is the son of a police officer. Bell also has worked for the troubled municipal courts system of St. Louis County that, as I reported here at The Washington Post at the time, has preyed on county residents with onerous fines and fees. In fact, Bell was the court judge in one town and the prosecutor in another, a practice that’s a bit bewildering but wasn’t uncommon at the time I wrote about it. (I’m told that one person can no longer serve in both positions.)

Despite that experience, or perhaps because of it, Bell emerged this year as a reform candidate. He has promised to reform the cash bail system, to implement diversionary programs for low-level offenders, to assign prosecutors to improve relations with specific areas of the county, and to set up a Conviction Integrity Unit to look for and overturn wrongful convictions.

But as we’ve seen with Philadelphia’s Larry Krasner and elsewhere, even when elected with overwhelming majorities, reform-minded prosecutors can expect resistance from entrenched interests who benefit from the system as it exists now. (The new St. Louis city prosecutor, Kim Garner, is also a reformer. This year she both announced that she’d no longer be prosecuting low-level marijuana possession cases, and submitted the names of 28 police officers from whom she said her office would no longer be taking cases, due to concerns about veracity.)

And so with Bell’s election, the county’s career prosecutors are now looking to unionize. The sudden interest in union representation likely comes from fears that Bell will clean out the old guard upon taking office. In theory, career prosecutors should adopt the agenda and priorities of the incoming county prosecutor-elect. But career prosecutors aren’t likely to be all that receptive to Bell’s agenda. So unionizing could make it tough for Bell to implement reforms by providing additional job protections to any prosecutors who refuse to play along.

But as St. Louis Post-Dispatch columnist Tony Messenger writes, it’s also about which union the prosecutors want to join — they want to be represented by the police union. The St. Louis Police Officers Association is one of the most aggressive police unions in the country. Its figurehead (though he no longer officially leads the organizations) is, Jeff Roorda, a former cop who was once fired for making false statements and filing a false report. Roorda is also a former state legislator, where he sponsored bills such as one that would have forbid anyone from publicizing the name of any police officer involved in a shooting unless that officer was charged with a crime. He once blamed the 2016 massacre of police officers in Dallas on Barack Obama. You get the picture.

But even putting Roorda aside, the conflict problems with having the same union represent both prosecutor and police officers are pretty obvious. What happens if a prosecutor charges a police officer for a shooting, and the officer then files a complaint against that prosecutor? Which party does the union defend?

The mere appearance of conflict is just as much of a problem. In St. Louis in particular, this will only further poison the relationship between law enforcement and the city’s communities of color. McCulloch’s handling of the Brown shooting was widely criticized not only because the grand jury ultimately declined to bring charges against Officer Darren Wilson but also because McCulloch seemed reflexively defensive of cops, in that case and others, and appeared to have decided early on that Wilson was innocent. Having the same union represent both cops and prosecutors certainly won’t help with the public perception — particularly in the black community — that St. Louis prosecutors will always back the cops.

But the unionization effort mostly seems to be a direct attack on Bell and his promised reforms. The union endorsed McCulloch, and Bell was extremely unpopular with police partisans such as Roorda. Since Ferguson, no organization has been more defensive of police practices and hostile to reform than the SLPOA. Now, the prosecutors who will report to Bell might vote to join the union that endorsed his opponent and that has opposed nearly every change he is promising to make.

Reform never comes easy. It’s especially difficult when there are entrenched powers whose livelihood depends on the status quo. The vote is scheduled for this afternoon.