Patients in pain have become collateral damage in the war on opioids.

That’s the message of a letter from more than 300 medical professionals, including three former White House drug czars, to the Centers for Disease Control. In 2016, the CDC issued guidelines to discourage doctors from overprescribing opioids. The signatories believe that those guidelines are being misapplied in a way that keeps many patients in agony.

Among policymakers, however, the focus is still on cracking down on prescriptions. Thirty-three states had imposed some type of limit on opioid prescriptions by last October. Democratic Senator Kirsten Gillibrand of New York and Republican Senator Cory Gardner of Colorado are pushing for a federal limit. Under their legislation, initial prescriptions for acute pain could cover no more than seven days and include no refills.

In the senators’ press release, Gardner says: “As I’ve met with Coloradans impacted by the opioid epidemic, the recurring story is clear. Oftentimes, the first over prescription spurs the devastating path of addiction.”

Gillibrand concurs: “One of the root causes of opioid abuse is the over-prescription of these powerful and addictive drugs.”

The bipartisan pair of senators have the same mindset that led then Attorney General Jeff Sessions to recommend last year that people in pain “tough it out” with aspirin rather than opioids. President Donald Trump, too, has called for reducing opioid prescriptions. “It’s so highly addictive,” he has said. “People go into a hospital with a broken arm; they come out, they’re a drug addict.”

This understanding of the opioid crisis has less and less grounding in reality. Illicit drugs, rather than prescription medications, have accounted for an increasing proportion of deaths from opioids.

The CDC reports 47,600 opioid overdose deaths for 2017. Heroin was involved in 15,500 of them. A drug category that mainly represents manufactured fentanyl and similar drugs was involved in 28,500.

Pain medications, meanwhile, were involved in 14,500: too many, but a minority of all cases. In some of these cases, illicit substances were also present. (The numbers for each category add up to more than the total because many overdoses include more than one drug.) The heroin- and fentanyl-related deaths have been rising much faster than the medication-related ones.

Other research suggests that prescription opioids are acting less and less as a “gateway drug” for opioid abuse. More and more opioid abusers are starting with heroin. Between 2005 and 2015, the percentage of opioid abusers who started with heroin grew from 9 percent to 33 percent.

Pain patients, contrary to a common view, have a low rate of addiction to opioids when you look closely at the research. A study of nearly 570,000 people who took opioids after surgery received attention when it was published last year for concluding that prescription refills were associated with a “large increase” in rates of misuse.

But the overall rate was low, including less than 1 percent of the sample. My American Enterprise Institute colleague Sally Satel reviewed some of the other research for Politico last year.

The campaign against over-prescription of opioids has succeeded in affecting medical practice. The prescription rate peaked in 2012 and has fallen steeply in recent years.

One might have hoped that by reducing the number of addicted patients and keeping excess medicines from being available for diversion into the street market, reducing prescriptions would dent the death toll from opioids. But during this period, the overdose-death rate has kept climbing: Those 47,600 deaths in 2017 set a new record.

It’s to Gardner and Gillibrand’s credit that their bill does not apply to prescriptions for chronic pain. The pleas of physicians and patients about the costs of the prescription crackdown may be starting to be heard.

But the record of recent years raises the question of whether a federal crackdown is a good idea in the first place. It misidentifies the root of the problem: It mostly has to do with people who are seeking out opioids for abuse, not who got addicted from prescriptions.

It is accompanied by a lot of counterproductive political rhetoric that discourages people from getting safe treatment for pain by telling them they will become addicts. And it does not seem to be succeeding in its fundamental aim of saving lives.

Each year, nearly as many Americans are dying from opioids as died in the entire Vietnam War. Increased interdiction of drugs at the border and funding for drug courts and treatment may help reduce those harrowing numbers. A continued bipartisan focus on prescriptions, though, will guarantee that too much of the war on opioid abuse will keep being fought on the wrong front.

Ramesh Ponnuru, a Bloomberg Opinion columnist, is a senior editor at National Review and visiting fellow at the American Enterprise Institute.