An unlikely bunch gathered just south of Washington, D.C., Monday at Maryland's National Harbor: White House Drug Czar Gil Kerlikowske, actor Matthew Perry, and former crack and heroin addicts.

They were there to talk about drug courts – programs that provide nonviolent drug offenders with treatment instead of a jail sentence. The number of drug courts has exploded in recent years along with rising numbers of drug offenders. In 1989, just one drug court existed in the U.S.; today, there are over 2700.

It's a system that's been wholeheartedly embraced by the Obama administration, which says the combination of incentives and sanctions, drug testing and care helps more people kick their drug habit and avoid ending up behind bars. Research has shown that drug courts save taxpayer dollars, too.

"More and more people are realizing that they can turn their lives around," Kerlikowske said at Monday's conference, which was hosted by the National Association of Drug Court Professionals.

And yet drug reform groups and lawyers who have worked with drug courts remain stubbornly unconvinced.

The Drug Policy Alliance, whose primary goal is to "end the war on drugs," released a report in 2011 called "Drug Courts Are Not the Answer." The report argued the converse of what previous studies on drug courts had shown, saying they could actually end up costing more money and lead to longer incarceration for some offenders.

Ethan Nadelmann, the founding executive director of the group, says the problem with drug courts is that participants only avoid jail time if they can manage to go cold turkey. "Typically it's the case that people relapse if addicted ... and then somebody who only had a minor drug problem may start getting re-incarcerated over and over again," he says.

In 2011, "This American Life" showed how harsh a drug court could be. A defendant in Georgia interviewed by the public radio show had forged checks worth $100, chosen to go through drug court, and ended up serving a decade in prison because of her failures to comply with the court's requirements.

But proponents of drug courts contend that story is an outlier, along with Albert Zweig, a former heroin addict who says he experienced nothing but compassion when he went through the Denver Drug Court and came out clean. "I went from being homeless and a disaster to finding a job and a place to live," says Zweig, who later went on to law school and today serves as a magistrate judge in the Denver District Court.

Paul Zukerberg, an attorney who represents marijuana defendants in D.C., believes drug courts often work for people like Zweig, who were addicted to heroin or other opiates, but not for users of lesser drugs like marijuana.

"They are not effective for anyone who doesn't believe that they have a drug problem – like the majority of marijuana users," he says.

According to a Department of Justice report, the majority of drug court participants are abusers of alcohol or marijuana, while a smaller number are abusers of cocaine/crack, methamphetamine, illicit opiates and prescription medications.

But even those who take issue with drug courts acknowledge the system has very real benefits.

Allen St. Pierre, the executive director of NORML, a nonprofit that works for marijuana legalization, calls drug courts a "mixed bag" and says they are an important "safety valve" for drug offenders to avoid incarceration.

In a second DOJ study, the agency found that 84 percent of drug court graduates were not re-arrested with a serious crime in the first year after graduation, and that 72.5 percent had no arrests after two years.

Nadelmann at Drug Policy Alliance, acknowledges that drug courts have a role to play. "But some are playing it," he says, "and some are not."