Philadelphia is trying to open a supervised drug consumption site to help stem the tide of overdose deaths in the opioid epidemic — but now President Donald Trump’s Department of Justice is suing a nonprofit in the city to stop the site, Bobby Allyn reported for local radio station WHYY on Wednesday.

Supervised consumption sites, also known as safe injection sites, are spaces where people can use drugs with sterile syringes and the supervision of trained staff, with the opioid overdose antidote naloxone and other medical equipment at the ready if anything goes wrong. The sites may also link people to addiction treatment on request.

The idea: While in an ideal world no one would use dangerous and potentially deadly drugs, many people do. So it’s better to give these people a space where they can use drugs with some sort of supervision. It’s a harm reduction approach.

But the Trump administration has spoken out against the idea, calling the sites illegal under federal law. Deputy Attorney General Rod Rosenstein, who published an op-ed in the New York Times on the topic, previously issued, on WHYY, a warning to Philadelphia officials about the city’s potential safe injection site: “It remains illegal under federal law. And people engaged in that activity remain vulnerable to civil and criminal enforcement.”

In the latest move, the Justice Department escalated its threats into action, filing a civil lawsuit against Safehouse. With support from city officials, the nonprofit is trying to open a supervised consumption site in Philadelphia as soon as this year, which would make it the first government-sanctioned site in the country. The site won’t get taxpayer dollars; it would be privately funded.

“This is in-your-face illegal activity using some of the most deadly, dangerous drugs that are on the streets,” William McSwain, US Attorney for the Eastern District of Pennsylvania, told WHYY. “We have a responsibility to step in.”

The Justice Department has cited a federal law originally meant to stop crack houses. It previously noted, in response to a proposal in Vermont, “It is a crime, not only to use illicit narcotics, but to manage and maintain sites on which such drugs are used and distributed.”

McSwain suggested that the Justice Department could have tried to take harsher action against Safehouse. “We’re not bringing a criminal case right now. We’re not arresting anybody. We’re not asking to forfeit property. We’re not looking to be heavy-handed,” he told WHYY. “This can serve everyone’s interest in order to find out what the court thinks of this. But this, in our view, is illegal.”

Safehouse argues that the federal crack house statute isn’t meant to stop medical facilities, like a supervised consumption site, focused on helping people survive and overcome their addiction. “We have a disagreement on the analysis and intention of the law,” Ronda Goldfein, vice president and lawyer for Safehouse, told WHYY.

Despite the federal government’s threats, several cities, beyond Philadelphia, have moved toward establishing their own safe injection sites as a way to combat the opioid epidemic. With drug overdose deaths reaching a record 70,000 in 2017, and about two-thirds of those deaths involving opioids, local officials are desperate to do anything to slow down the crisis — and safe injection sites, based on some of the research, may help do that.

Now the federal government’s lawsuit could help decide whether these sites are legal.

There’s some evidence for supervised consumption sites

Advocates say supervised consumption sites can save lives, citing some of the research done on the facilities in Australia, Canada, and Europe. Drawing on more than a decade of studies, the European Monitoring Centre for Drugs and Drug Addiction in 2018 concluded that safe injection sites led to “safer use for clients” and “wider health and public order benefits.” Among those benefits: reductions in risky behavior that can lead to HIV or hepatitis C transmission, drops in drug-related deaths and emergency service calls related to overdoses, and greater uptake in drug addiction treatment, including highly effective medications for opioid addiction.

A recent review of the evidence from the RAND Corporation was more cautious. RAND found that there aren’t many well-conducted studies on safe injection sites, and the studies that do exist are too few and far between and have too many methodological constraints and weaknesses to reach hard conclusions about the sites’ overall effectiveness. “It’s not that you can’t learn anything from those studies,” Beau Kilmer, lead author of RAND’s report, told me. “But you have to be really careful.”

Critics, meanwhile, argue that supervised consumption sites will enable more drug use by creating a space where using drugs is tolerated.

But none of the research done so far — not even the more cautious RAND review — has found evidence that supervised consumption sites cause more harm. In fact, while fears of enabling more drug use are a common talking point against harm reduction approaches, from needle exchanges to naloxone to supervised consumption sites, none of the empirical work on these issues has found solid proof that they significantly increase drug use. It’s just not an evidence-based claim.

That’s not to say that the research on supervised consumption sites is perfect. Given that the evidence so far comes from just a few sites in other countries, much more research is needed, particularly for how a site could work in the US. But to get that, someone has to actually open a legally sanctioned site in the US first. And while there are illegal sites around the country, so far nobody has opened one that’s sanctioned by any government — local, state, or federal.

In the past couple of years, several US cities have said they want to change this, including Philadelphia as well as New York City, San Francisco, and Seattle. Advocates don’t believe that supervised consumption sites are a silver bullet to addiction and overdose, but they say the sites could play a crucial part in a broader approach to the opioid crisis.

The Trump administration disagrees. And now they’re taking some of the people involved with safe injection sites to court to prove their case.

For more on safe injection sites, read Vox’s explainer.