There are good reasons to oppose or be skeptical of America’s 45-year-old War on Drugs. There are also good reasons to fear that legalizing drugs would produce a spike in consumption and addiction. Amid our current nationwide drug-overdose epidemic — an epidemic visible everywhere from New Hampshire to New Mexico, and from Staten Island to Seattle — such fears should not be taken lightly.

Whatever we think about the efficacy or morality of the drug war, it’s important not to exaggerate or distort its impact on the criminal-justice system. Writing in the Wall Street Journal, scholar Barry Latzer, an emeritus professor at CUNY’s John Jay College of Criminal Justice, notes that the sharp rise in U.S. incarceration rates during the last few decades of the 20th century — a phenomenon that critics have dubbed “mass incarceration” — was driven mainly by violent crime rather than by drug offenses.

Indeed, it’s easy to forget that, between 1961 and 1991, America’s violent-crime rate increased by 380 percent, with the murder rate increasing by 104 percent. This historic surge of violence, writes Latzer, is the chief reason we saw an historic surge of prisoners. Since then, however, violent crime has fallen precipitously: The nationwide rate declined by 50 percent between 1991 and 2014. (In 2015, unfortunately, “the number of homicides in the country’s 50 largest cities rose nearly 17 percent,” which amounted to “the greatest increase in lethal violence in a quarter century,” according to the Washington Post.)

Not surprisingly, the change in crime rates led to a change in incarceration rates. Here’s Latzer:

When crime began to drop in the mid-1990s, so did the rise in incarceration rates. From 2000 to 2010, they increased a negligible 0.65%, and since 2005 they have been declining steadily, except for a slight uptick in 2013. The estimated 1.5 million prisoners at year-end 2014 is the smallest total prison population in the U.S. since 2005.

Those who talk of “mass incarceration” often blame the stiff drug sentences enacted during the crack-cocaine era, the late 1980s and early ’90s. But what pushed up incarceration rates, beginning in the mid-1970s, was primarily violent crime, not drug offenses.

The percentage of state prisoners in for drug violations peaked at only 22% in 1990. Further, drug convictions “explain only about 20% of prison growth since 1980,” according to a 2012 article by Fordham law professor John Pfaff, published in the Harvard Journal on Legislation.

Relatively few prisoners today are locked up for drug offenses. At the end of 2013 the state prison population was about 1.3 million. Fifty-three percent were serving time for violent crimes such as murder, robbery, rape or aggravated assault, according to the BJS. Nineteen percent were in for property crimes such as burglary, car theft or fraud. Another 11% had been convicted of weapons offenses, drunken driving or other public-order violations.

That leaves about 16%, or 208,000 people, incarcerated for drug crimes. Of those, less than a quarter were in for mere possession. The rest were in for trafficking and other crimes. Critics of “mass incarceration” often point to the federal prisons, where half of inmates, or about 96,000 people, are drug offenders. But 99.5% of them are traffickers. The notion that prisons are filled with young pot smokers, harmless victims of aggressive prosecution, is patently false.

To read the whole thing, go here. (Latzer’s article draws on material from his new book, The Rise and Fall of Violent Crime in America, published last month by Encounter.)