By Eugene Robinson

Oscar-winning actor Philip Seymour Hoffman is yet another victim of the war on drugs. Prohibition is not working. It is time to try something new.

Hoffman, 46, was found dead in the bathroom of his Manhattan apartment Sunday morning, apparently the victim of a heroin overdose. According to widely published reports, there was a syringe in his arm. Police found the place littered with small plastic bags stamped “Ace of Spades” or “Ace of Hearts” — brand names that street dealers use.

Hoffman had lived through a familiar pattern: experimentation, addiction, rehab, abstinence, relapse, more rehab, more abstinence, another relapse.

Why would a man held in such high esteem, a man with so much going for him and so much to live for, risk it all by buying illegal drugs from a criminal on the street and then injecting them into his veins? For the same reason any addict uses drugs: to get high.

Perhaps this desire was a moral failing on Hoffman’s part. Perhaps its origin lies buried in his personal history, with some trauma having triggered it. Perhaps it was written in his genetic code. I doubt we’ll ever know for sure.

We do know that this need to get high is beyond some people’s control. Our drug policy of prohibition and interdiction makes it difficult and dangerous for people like Hoffman to get high, but not impossible — and it makes these tragic overdose deaths more common than they have to be.

The obvious problem is that when an addict buys drugs on the street, he or she has no way of knowing how pure the product is and what else it might contain. In recent months, according to health officials, 37 people have died in Maryland, 22 in western Pennsylvania and several others in Ohio and New York from injecting heroin adulterated with fentanyl, a synthetic opioid that can be up to 100 times more potent than morphine.

It makes sense that addicts would try to purchase only from dealers they trusted. It also makes sense that dealers selling a heroin-fentanyl mix would warn buyers of its potency, since killing the customers is bad for business. But remember that addicts use drugs to get high. Being told a certain batch of heroin would get them higher than usual might sound to their ears like a promise, not a threat.

As long as this commerce is illegal, it is totally unregulated. Since we know that addicts will continue to buy drugs on the street, we also know that some will die from drugs that are either too potent or adulterated with other substances that could make them lethal. Is this really the intent of our drug policy? To invite users to kill themselves?

The idea is supposed to be that authorities will somehow keep the drugs from entering the country. This would be a joke if it weren’t such an epic tragedy.

In the 1990s, when I was The Post’s correspondent in South America, I watched as U.S. Drug Enforcement Administration (DEA) agents played Whac-A-Mole with the cocaine industry. They’d harass the coca growers in Peru, only to see more acreage planted in Bolivia. The agents would go to work in Bolivia, only to see coca plantations sprout up in Colombia. By the time the DEA had marshaled its assets in Colombia, the fields were lush and green once more in Peru.

A couple of times, authorities in these countries flew me out to see fields of opium poppies they had discovered — the drug lords were diversifying into heroin. But the epicenter of poppy cultivation is Afghanistan, where U.S.-backed officials turn a blind eye.

When you talk to leaders in the countries that produce or ship illegal drugs, they all say the same thing: We wouldn’t have a drug industry if there were no demand. You’re the ones who put this stuff in your veins and up your noses.

They’re right. And since we obviously don’t know how to eliminate this demand, we need to try some new approaches.

For marijuana, we should follow Colorado and Washington toward legalization. Addiction to harder drugs should be considered a medical problem, period — a chronic illness, like diabetes, that might not be curable but can be managed.

There would be times when managing addiction means prescribing to addicts pharmaceutical-grade heroin and other drugs and then medically monitoring them. There would be other times when it means treatment to get clean. Philip Seymour Hoffman had tried and failed, tried and failed. But who knows? Next time, he might have made it.