What's the job of the Philadelphia district attorney?

Is it to put people away in prison?

Or to ensure justice gets done?

Those two phrases often get used as though they are interchangeable. They are not.

Not in a city that jams people into overcrowded jails, at a per capita rate twice the national average.

Not in a city where the average time spent in jail awaiting trial (95 days) is four times the national average.

Not in a city that pays $10 million a year to settle cases of police misconduct.

Not in a city where political corruption (both petty and grand) is epidemic - reaching right into the D.A.'s office itself.

And where blacks are more likely to be arrested on minor drug charges, more likely to be imprisoned for nonviolent crimes, more likely to receive longer sentences than whites for the same crimes.

None of that is justice. Much of what Black Lives Matter decries remains painfully true - and the deep well of facts that undergird its anger is a stain on the American flag.

Philly district attorneys past and present have had a hand in all those flaws.

These ills can and should be addressed by the next occupant of the office, whichever one of eight candidates (seven Democrats, one Republican) replaces the indicted Seth Williams.

Williams rode into office seven years ago promising a wave of reforms. He produced a trickle - apparently because so much of his energy went into chasing alleged improper gifts.

The city desperately needs a district attorney who brings a broader vision to the office, who sees the job as more than just racking up guilty verdicts and pleas.

We need a D.A. who sees the job as ensuring, on multiple fronts, that justice is done.

Who understands that the job includes exonerating the wrongly accused - while prosecuting cops who lie on the stand.

Who recognizes that you can't just shrug or wink at corrupt pols - even the ones who supported you in the last election.

Who gets that jails bursting at the seams are a sign of failure, not success.

None of this is to ignore that the decent folks in the neighborhoods deserve safe streets.

Nor that some bad actors deserve to be sent away for a very long time.

Nor that most police officers do dangerous, difficult work with courage and integrity.

With all that acknowledged, the city still needs a more balanced, "woke" approach to justice.

The district attorney is the fulcrum of any such effort - joining the mayor and school superintendent in the trinity of the most important public jobs in town.

The district attorney sets the standards for which cases get brought to trial, which are scrapped because the police work was shoddy or tainted by bias. The district attorney can propel the system to seek alternatives to incarceration, saving the costly cells for the worst offenses and offenders. And it's the district attorney who should be the first, fierce line of defense against official corruption.

The stakes are so much clearer now than the last time Williams ran. Now, we go to the polls knowing about Ferguson, Mo., and Freddie Gray, and Tamir Rice. We've shaken our heads at the recent despicable parade of local elected officials caught violating the public trust.

In Philadelphia, this election demands our attention just as much as the one last Nov. 8.

Here is where the cynic says: Yeah, yeah, Satullo. So tell me, wise guy, what was the turnout last time in the D.A. primary?

Well, paltry. Williams won with just shy of 58,000 votes (about half of what he got when he first won the job in 2009).

Let's do a little speculative math. Split the difference in turnout between the last two primaries where the D.A.'s office was on the ballot. Let's say 85,000 Democrats vote in May. What if the seven Dems on the ballot split the votes fairly evenly? That means the winner could have as few as 13,000 votes. Imagine it - that sliver of Philly Democrats essentially picking the next district attorney for the other 1.5 million souls living in this city.

Crazy. Lamentable. A great argument for various reforms in how we do elections around here, such as open primaries and/or ranked-choice voting.

But none of those reforms will be in play on May 16, when the city elects the person who might do more than any other single living human to determine whether Philadelphia becomes more or less just.

This crowded, winner-take-all Democratic ballot is all we've got. So study up, Philly voters. And put a note on your Google Calendar for May 16: "Remember to vote."

Because we get the city we deserve.

Chris Satullo is a former Inquirer editorial page editor. centersquarephil@gmail.com.