A man walks past a banner prior to a rally on Tuesday in Oakland against long-term solitary confinement. (Robert Galbraith/Reuters )
Opinion writer

From the Black Lives Matter protests against police shootings, to the Koch brothers’ new campaign against excessive sentencing, the U.S. criminal justice system is under fire from all directions.

Indeed, if any cause can be said to enjoy bipartisan support these days, it’s reform of the police, prisons and law enforcement.

A hugely ironic, but seldom acknowledged, fact about this phenomenon is that it started when the various components of U.S. criminal justice — local, state and federal — were arguably performing their core mission — keeping the public safe — more effectively than at any time since the Kennedy administration.

The national homicide rate in 2013, the most recent year for which FBI data are available, was 4.5 per 100,000 people , roughly the same as 1962, and among the lowest of the post-World War II era. Just two decades ago, in 1993, the rate was 9.5 per 100,000; if that had been the rate in 2013, there would have been 30,067 murder victims, not 14,196, as actually occurred.

The downward trend over that period for all categories of crime, against people and property, is similar. This achievement, which was impossible according to much conventional wisdom of a quarter-century ago, is tremendous and historic, whether you measure the benefits in lives, dollars or peace of mind. Horrific as this summer’s surge in homicide is, it’s a far cry from the bad old days.

A disproportionate number of the lives saved over the past two decades were African American, for the sad but true reason that blacks were, and still are, several times more likely to be victims of violent crime than whites.

The homicide victimization rate for African Americans fell from a record 39.4 per 100,000 in 1991 to 18 per 100,000 in 2012, according to data compiled by the nonprofit Violence Policy Center. That is far too high, but the fact remains that African Americans were less than half as likely to be murdered as they were at the beginning of that interval.

Public perceptions reflect the changed reality. Whereas 52 percent of the public named crime as the top issue facing the country in August 1994, according to a Gallup poll, only 4 percent gave that answer in July , notwithstanding this summer’s ugly rash of homicides.

In a backhanded way, the widespread criticism of the cops, courts and prisons is a great compliment to them, their reward for whatever role they played in restoring social tranquility to the point where abuses or excesses by the authorities loom larger, in reality and perception, than crime itself.

When crime waves end, political space opens for more nuanced, and critical, discussion of crime-control policy. At its best, the reform movement reflects the view that aggressive anti-crime policies in reaction to the ’90s crime wave, such as “stop and frisk” in New York, are yielding diminishing returns, or that their costs, in terms of money, freedom and community sentiment, now exceed their benefits.

At their worst, however, critics reflect the Great American Free Lunch mentality, denying that there are tough choices and trade-offs in this policy area as in all others.

Nowhere is that tendency more evident than in the discussion of “mass incarceration,” sometimes portrayed as a simple matter of saving communities by locking up fewer people for “nonviolent” drug offenses. Win-win.

The facts say otherwise. Specifically, most state prisoners are in for violent offenses such as murder or armed robbery. The “inescapable” reality, as New York Times reporter Erik Eckholm put it in an Aug. 12 article, is “Big cuts in incarceration . . . will have to involve rethinking of sentences for violent criminals.”

Yet tougher sentences for violent criminals probably helped slash violent crime, if only by keeping dangerous people off the streets longer. In 1981, the average time served for murder was just five years. By 2000, it was up to 16.9 years. The numbers for rape were 3.4 and 6.6 years, respectively.

Independent of their crime-reducing effect, long sentences for horrific crimes also meet widespread public notions of justice. Eliminating life without parole for murder would certainly reduce the incarceration rate, but any such proposal might destroy the emerging consensus over criminal justice reform.

The percentage of Americans who believe criminals are not punished “harshly enough” declined from 85 percent in 1994 to 62 percent by 2012, according to polling data compiled by Mark Ramirez of Arizona State University — which implies voters are in a less punitive mood than they were at the height of the crime wave, but only tentatively.

What’s the “right” incarceration rate? Whatever the answer, we shouldn’t forget what it took to achieve America’s remarkable triumph over violent crime.

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