I don’t smoke marijuana, but like many other Yalies, I used to favor the decriminalization of pot and other drugs. The guy in my entryway rumored to smoke up twice a day always seemed benign enough, and the sticky-sweet smell that occasionally wafted through a party didn’t seem to warrant anybody losing their financial aid, let alone getting locked up.

A summer spent working in the probation department of a Connecticut courthouse changed my mind. Marijuana had distorted my view of the drug war; the government should distinguish more between marijuana and “hard” drugs like cocaine and heroin. I discovered two facts: hard drug use is far from a victimless crime, and, more importantly, the threat of incarceration helps those addicted get off drugs.

The usually laudable American Civil Liberties Union, arguing against criminal prohibition of drugs, states on its Web site that “unless they do harm to others, people should not be punished — even if they do harm to themselves.” But drug users inevitably harm others. It’s a simple, tragic cycle: hard drugs are incredibly addictive, and, once addicted, it’s virtually impossible for a drug user to hold down a job. A jobless addict has to pay for expensive drugs (not to mention food) somehow, so he breaks the law.

I wish this cycle were just theoretical, but I saw it happen to real people over and over again. Try calling up (as I did) four store clerks who’d been held at gunpoint by a crack addict coming off his high and desperately in need of cash, and tell them that drug use is victimless.

The person who drives his car after drinking eight beers doesn’t intend to hurt anyone, but drunk driving inherently infringes on my right to personal safety. Drinking alcohol, on the other hand, isn’t inherently dangerous; the vast majority of people who consume alcohol do so safely. But hard drug use is more like drunk driving than it is like drinking; drug addicts and drunk drivers both will eventually harm someone else.

Before this summer, though, I didn’t think that prohibiting drugs actually prevented people from using them. I knew that the law couldn’t stop everyone from trying drugs, and I knew that addicts needed to be very self-motivated to quit.

Yet, I’d underestimated how much incarceration helps drug addicts gain this motivation. Virtually all the addicts I met agreed on one fact: being in and out of jail was ruining their lives. A heroin addict may not acknowledge heroin’s cost to society, but you better believe he’ll try to kick a heroin habit if it means he can keep himself out of jail.

The government should use that motivation, always keeping in mind that the point of drug prohibition is to help addicts quit, not unnecessarily punish them. The best drug laws give drug addicts opportunities to enter treatment clinics and rehabilitation centers while holding the threat of jail time over their heads. Connecticut, thankfully, isn’t like New York, with its horrific 1970s-era Rockefeller laws that mandate minimum sentences for drug offenses. Instead, Connecticut has a plethora of “pre-trial diversionary” and “alternatives to incarceration” programs, not to mention probation departments, which treat first and use incarceration only as a last resort.

When these programs fail, some of the most effective drug treatment can take place within prison walls. As one addict I met put it, “addiction is a powerful and cunning disease,” so powerful that the temptation to leave rehab can be too much, even for the most motivated. Prisons, at the very least, stop addicts from leaving before their treatment is finished.

The judge in a courtroom I frequented has a stack of “thank you” letters from former addicts treated at the Maryland-Baker House, a part of York Correctional Facility in Niantic and arguably the best drug rehab center in the state. If drugs were legal, where would these people be now?

Brad Lipton is a sophomore in Branford College. He is a member of the Yale Daily News editorial staff.