Opinion editor's note: Star Tribune Opinion publishes a mix of national and local commentaries online and in print each day. To contribute, click here.

•••

In general, American progressives think the U.S. could learn a lot about enlightened public policy from other developed nations, particularly the social democracies of Europe — on everything from health care to gun control to genetically modified foods and beyond.

In general, American conservatives are skeptical.

Both sides might be surprised to learn what's revealed by carefully comparing the basic approach to criminal justice at work in the United States with that prevailing in the rest of the "First World."

In a fascinating new study, two impeccably progressive Harvard professors argue that "the American criminal legal system is unjust and inefficient." If that conclusion seems less than startling from such a source in these days of strife over police violence and surging crime, wait for their diagnosis of the problem.

"Over-policing is not the problem," say law Prof. Christopher Lewis and sociologist Adaner Usmani. What handicaps U.S. law enforcement and differentiates it from what they call the "First World Balance" is "an exceptional kind of under-policing" (emphasis theirs).

It's widely acknowledged that two years after the start of the COVID pandemic, and two years after the murder of George Floyd and subsequent civic unrest, many American cities are suffering an acute shortage of police officers — not least Minneapolis. But Lewis and Usmani say underpolicing is a far deeper and longer-term issue.

Indeed, in "The Injustice of Under-Policing in America" (American Journal of Law and Equality), Usmani and Lewis report it's not merely that America deploys a below-average number of cops relative to population, compared with a sample of peer nations including France, Germany, Belgium, Australia, Italy, etc. They add that when more meaningfully measured in relation to the level of violent crime cops are combating in various nations, "the level of policing in the United States appears exceptionally low compared to other countries."

Measured as police officers deployed per homicide, the law enforcement presence on American streets is far below that of Japan, the Netherlands, Norway and Switzerland, the researchers show. And America also has substantially fewer cops on the street, measured this way, than do Canada, Denmark or Sweden, among others.

Overall, "America has about one-ninth the number of police officers, per homicide, as does the median developed country," they write.

But what of "mass incarceration"? Well, it's real, and Lewis and Usmani have much to say about it, reporting that relative to population, America's inmate count is far greater than any other developed nation's. Their forthcoming book, from which the journal essay is drawn, is titled "What's Wrong with Mass Incarceration."

Essentially, they argue that the U.S. criminal justice system attempts unsuccessfully to compensate for its radical underpolicing of communities with "a heavy reliance on long prison sentences, compared to other developed nations."

Ruined lives and blighted communities follow, these researchers agree. Yet America's tragic crime rates persist. Lewis and Usmani argue that peer countries maintaining the "First World Balance" do better by confronting would-be offenders with a high probability of apprehension and punishment, albeit comparatively mild punishment. America has opted for a low-probability of punishment due to underpolicing (and resulting low clearance rates for crimes) combined with harsh prison terms for those who are unlucky enough, or persistent enough in their lives of crime, to be caught.

Among the other unfortunate results these scholars see for America from this low-probability/high-severity system are: 1) too many particularly dangerous and desperate offenders willing to flee and/or shoot it out with police to avoid the system's harsh consequences — and 2) as a result, nervous cops with a warrior mind-set.

According to their research, write Usmani and Lewis, "Countries with larger numbers of police per homicide are countries in which police are much less likely to kill civilians" (emphasis theirs).

It almost goes without saying that these alleged consequences of underpolicing — long prison terms, high rates of particularly violent offending, fewer crimes solved and edgy cops — all do most of their damage in disadvantaged minority communities.

Lewis and Usmani note, meanwhile, that as harmful as mass incarceration is in America, when adjusted for the rate of serious crime, "America's outlying level of incarceration looks relatively ordinary. Its prisoner-per-homicide ratio is a little higher than the developed-world median, but not by much."

There is a great deal more to be found and learned in what is, as noted, an intriguing and constantly surprising work of research. In the end Lewis and Usmani simply recommend a program progressives often endorse. America, they suggest, should emulate, say, Denmark and Norway, adopt the "First World Balance" and redirect many of the billions of dollars it spends on prisons to putting more police, lots more police, on the street. Punishment would become more certain (but less severe), and they believe crime, incarceration and police brutality all would decline.

They concede that on both the left and the right, the "pessimistic tone" of their work and the more heavily policed America they envision might raise serious "civil libertarian" concerns. In fact, such concerns could prove insurmountable. But the challenging facts and ideas in "The Injustice of Under-Policing" repay careful consideration, whatever one's ideological leanings.

For their part, Lewis and Usmani are progressives, at pains to declare their belief "that in the long run, a significant expansion of social policy would reduce crime by addressing its root causes … . But a significant expansion of social policy [would require] significant redistribution from rich to poor. ... Given ... the electoral fracturing of the American working class, we doubt we will see anything like this soon."

But to their great credit, Lewis and Usmani do not assume their work is done once they have explained the many ways reality is not meeting their expectations.

"Our aim in this essay," they write, "is to say something useful about what should be done in the non-ideal world in which we live — not just in the ideal world in which we would like to live."

I salute them.

D.J. Tice is at doug.tice@startribune.com