Pima County voters have a rare choice between a county attorney who wants to limit the number of people we send to prison and a challenger who really, really wants to limit the number of people we send to prison.

This Democratic primary, which will likely decide the winner because there’s no Republican challenger, is not a get-tough-on-crime campaign. It's unlikely the general-election race against Green Party candidate Cyndi Tuell will be either.

In the primary, the main argument challenger Joel Feinman has been making against incumbent Barbara LaWall boils down to: She puts too many people in prison and not enough into diversionary programs.

That was the background last week when LaWall and Feinman traded op-eds on the Star’s editorial page.

LaWall’s main point on Wednesday: We are putting the right people in prison.

Feinman, on Thursday, argued it’s un-American to imprison people at the rate we do.

The evidence that Arizona’s incarceration rate is out of whack seems obvious.

We have almost 43,000 prison inmates in our state system, 5,100 of whom are at the prison complex here in Tucson. That’s far more than any other state Arizona’s size. Indiana for example, has about the same population and 26,000 state prisoners.

The Prison Policy Initiative, an anti-mass imprisonment group, ranked the world’s countries and each of the U.S. states in a chart to show how each state’s incarceration rate compares to others and to world rates.

On a global scale, Arizona ranked seventh overall, behind five other states and the District of Columbia. No other country comes into play until Turkmenistan interrupts the roll-call of U.S. states at No. 35.

So, in Arizona, we’re a Top 10 world leader in locking people up.

Some of the blame for this comes from state laws. Not only are there mandatory minimum sentences in Arizona, but all prisoners, not just violent offenders, must serve at least 85 percent of the sentence imposed — a harsher standard than almost any other state.

Those laws also mean the power over who goes to prison has shifted away from judges, because they no longer have much discretion, and over to prosecutors and police officers.

When we spoke Friday, LaWall pointed out that her office must consider all the cases that police agencies submit — and that volume is growing fast. It went from a little over 9,000 filings in fiscal-year 2015 to a little over 11,000 in 2016, she said. There’s no way that kind of increase will not result in more rightful felony convictions and imprisonments.

But while police officers are one of the main drivers of the numbers, prosecutors have discretion over what charges get filed. Some new research suggests that nationwide, prosecutors are filing many more felonies per arrest than they used to.

A Fordham University criminal-justice professor, John Pfaff, reported that nationwide from the mid-1990s to the late 2000s, the proportion of arrests resulting in felony charges went from about one in three to about two in three.

“At least since 1994,” he concluded in a 2013 paper, “it appears that almost all the growth in prison populations has come from prosecutors’ decision to file felony charges.”

LaWall argues that the right people are going to prison and points to a report commissioned by the Arizona Prosecuting Attorneys’ Advisory Council. The bottom-line figure from the report, repeated often since it first came out in 2011: 94 percent of prisoners are violent or repeat offenders.

“The data we have very clearly shows we are not putting in prison first-time, nonviolent, low-level offenders,” LaWall said. “The people in prison are those who have violent offenses or repeat offenses or violent and repeat offenses.”

Feinman, who wrote his op-ed before LaWall’s had been published, noted later that the report she’s relying on has itself been debunked and pointed to the latest monthly report from Arizona’s prison system as evidence of how wrong it is. That report, from July, says 50.7 percent of inmates were serving their first term, and 28 percent were nonviolent offenders.

It also says, though, that 12.9 percent of Arizona’s prison population was sentenced in Pima County, which has 14.9 percent of the state’s population. So, our prisoners make up a slightly smaller than proportional share of the state’s prisoners.

This wouldn’t matter so much if the stakes weren’t so high.

On the one hand, there are the lives of the growing ranks of prisoners. A felony conviction can ruin a person’s record, leaving no job prospects and no place to live. Time in prison is as likely to keep a person screwed up as to fix him or her.

“We’re actually creating our own problem with these policies,” Caroline Isaacs of the American Friends Service Committee told me.

“If you’re an addict, we’re not going to incarcerate the drug addiction out of you.”

The story of Colleen Johnson comes to mind. In a case the Star has written about, the Pima County Attorney’s Office chose to refile DUI charges against her, leading to her imprisonment despite her having regained her footing as a functional member of society. In prison this spring, she was diagnosed with cancer, received the health care afforded inmates, and quickly died.

But on the other hand, there are the lives of the victims and potential future victims to consider. Even property crimes, LaWall noted, are classified as nonviolent, but they don’t necessarily feel that way to the victims.

“Three times I’ve been the victim of a burglary,” LaWall said. “It’s a traumatizing, violent offense against me, the security of my home and my feelings of sanctity and security.”

I asked her about Johnson’s case, and she noted the number of people killed and maimed in DUI crashes . It’s true — there’s a risk in putting repeat offenders like Johnson back on the streets when they’ve relapsed and offended again before.

Prison doesn’t seem like the solution, but it’s the main one Arizona’s been willing to give so far. How little of it we will use — that seems to be the choice before the county’s Democratic primary voters.

Contact: tsteller@tucson.com or 807-7789. On Twitter: @senyorreporter