Calling the idea "fundamentally illegal," the region's top federal law enforcement official is vowing that his office will take measures — possibly including arrests and prosecutions — to prevent Philadelphia from becoming home to the nation's first safe injection site.

In an interview Friday with the Inquirer and Daily News, U.S. Attorney William M. McSwain said he did not doubt the good intentions of a coalition of local advocates, including former Gov. Ed Rendell, that announced plans this month to open such a site.

But he is already reviewing possible options to stop them, ranging from court orders to block the opening of the facility to criminal forfeiture proceedings against the operation.

"The bottom line is that the sort of facility that is being proposed is illegal under federal law," the U.S. attorney said. "We're not going to look the other way."

Supporters contend their plan is legal, and they intend to proceed. No site has been finalized, but backers have indicated it's likely to open in Kensington, the neighborhood that has become both the center and public symbol of the city's deadly opioid epidemic.

McSwain declined to commit to any specific action during the interview at his office across from Independence Hall. Still, the options he described offered the most concrete outline yet of the federal government's potential response should the proposal's backers move forward. They also seemed to signal a looming court battle that could decide the legality of supervised injection sites across the United States.

"Nobody is above the law – and by that I mean nobody," McSwain said. "I mean the leaders who would be involved in setting up this proposed deadly drug injection site, the board members … the city officials who would be involved in supporting it, the medical personnel who might be staffing it or the folks who might be using the drugs."

A handful of cities, including New York and Seattle, have also inched closer to making such sites a reality in the last year as they struggle to combat an opioid crisis that has led to thousands of deaths and resisted traditional prevention measures.

And while the Justice Department has broadly opposed the idea, it has been reluctant to spell out a nationwide policy on how it might respond. Still, the comments by McSwain, who was appointed by President Trump and started in April, and similar remarks by Deputy Attorney General Rod Rosenstein in August, indicate that the office is girding itself for a courtroom showdown.

Despite those threats of court action, Jose Benitez — president of Safehouse, the Philadelphia safe injection site nonprofit — said he and his colleagues remain undeterred, especially in a city where 1,217 people died of overdoses last year.

"We are morally obligated to continue what we're doing," said Benitez, who also runs the city's only needle-exchange program, Prevention Point. "There are people out there dying, and we have to address that issue."

He and other proponents of safe injection sites say the controversial idea would provide people with addiction a space where medical staff could monitor their drug use, prevent potential overdoses, and offer drug treatment services.

City officials have said they would not stand in the way of such a facility in Philadelphia, though they would offer no funding. Pennsylvania's attorney general, Josh Shapiro, has come out against the idea, though he has not spelled out any steps he could or might take in response.

In that unsettled legal landscape, Rendell, Benitez, and Ronda Goldfein — the third member of the Safehouse board — this month took the first concrete steps toward establishing a safe injection site. They incorporated the Safehouse nonprofit and launched a fund-raising effort to amass the $1.8 million they say they will need to operate the facility in its first year.

Under their proposal, the site would ban drug dealing, drug sharing, exchanging money, and the sharing of needles or other drug paraphernalia. Participants would not be able to help one another use drugs, and staffers would not handle drugs taken to the site.

Goldfein – who is also executive director of the AIDS Law Project of Pennsylvania and married to David Lee Preston, an Inquirer and Daily News editor — said she and her colleagues have been consulting with lawyers should their proposals land them in court.

"We're respectful of the authority of [McSwain's] office," she said.  "But we are committed to taking these steps because we feel compelled to."

But even in their word choices the U.S. attorney and Safehouse's backers remain miles apart.

Both eschew the widely used term safe injection site. The nonprofit's backers refer to their proposal as an "overdose prevention site," while McSwain, throughout the interview Friday, used the term deadly drug injection site.

And even with the precautions Safehouse has laid out, McSwain views their plan as unworkable.

"It doesn't really matter that the city's not involved in funding it," he said. "It doesn't really matter that the city isn't literally grabbing the needles and injecting the addicts with the drugs themselves. They're setting up a drug house, and that's clearly illegal under our view."

Central to the dispute as he sees it is a 1986 federal law – known colloquially as the "crack-house statute" – which makes it a felony punishable by up to 20 years in prison to knowingly open or maintain any place for the purpose of manufacturing, distributing, or using controlled substances.

Proponents of supervised injection sites argue that the law, passed at the height of the crack cocaine epidemic, was not intended to interfere with good-faith efforts to improve public health.

"The intent of the crack-house law was to prohibit one type of conduct," Goldfein said. "We believe that our conduct is different from that" — namely, that Safehouse is working to prevent overdoses, not promote drug use.

McSwain maintains that the law is clear and that if projects like Safehouse are to move forward legally, then its backers should first lobby legislators to change it.

"There's no 'good-intention' exception to federal law," he said. "We don't say to a tax cheat: Well, don't worry about paying your taxes [just because] you think government is too big."

Safehouse's backers say they are prepared to accept the legal risks. Rendell quipped during an interview this month that he would "be happy to go to Allenwood, [a federal prison in Pennsylvania], and play tennis." Another member of the nonprofit's advisory board – homeless advocate Sister Mary Scullion – has also reportedly said she's prepared to face incarceration.

McSwain said he did not view such breezy rhetoric as helpful.

"I don't want to get the impression that people are laughing it up about getting arrested for violating federal law or joking about playing tennis at Allenwood or joking about arresting a nun," he said Friday. "It's not a laughing matter."

Still, McSwain said, he remains in communication with Rendell, Benitez, and other Safehouse backers and described the tenor of their conversations as "very pleasant, productive, and informative."

He toured Prevention Point in a converted church in Kensington on Wednesday — a meeting Benitez described as cordial but careful, as both men stuck to questions about the operations of the needle exchange.

"It never felt adversarial at all," Benitez said. "We were approaching the beginnings of a conversation."

Even still, they were interrupted by the epidemic that brought them together that day and threatens to put them at odds in the future.

As they talked, staff members rushed past them to treat someone overdosing on the sidewalk outside.

"We've seen a lot of things that can be described as gut-wrenching or heartbreaking," McSwain said Friday. "But we have a mission to enforce the law, and I think that's the most effective way to eliminate the human misery that we see in Kensington and elsewhere."