Supervised injection sites are poised to face their first legal test in the United States in a case that could set a precedent for New York and other states considering whether to allow places where people can inject heroin and other drugs in the care of medical professionals.

U.S. Attorney William McSwain filed a lawsuit in a federal court in Pennsylvania on Wednesday seeking to prevent the Philadelphia nonprofit Safehouse from opening what could be the country’s first supervised injection facility (SIF). He’s asking a judge to deem the planned facility illegal under the so-called "crack house" statute, which made it a felony to knowingly operate a site where controlled substances are used.

Despite Governor Andrew Cuomo’s eagerness to position himself in opposition to the federal government on everything from reproductive health to taxes, he and State Health Commissioner Dr. Howard Zucker have so far demurred in the face of President Donald Trump's Justice Department's opposition to SIFs. Four supervised injection sites that have been proposed as part of a de Blasio-endorsed pilot in New York City have been waiting months for the approval they need from the state.

“We have been actively working with advocates and the City on their proposal and on how to address the demonstrably real threat of federal legal challenges,” Hazel Crampton-Hays, a spokesperson for Governor Cuomo, said Wednesday. “We will evaluate the claims and issues raised in this federal lawsuit in Pennsylvania as part of our ongoing review.”

But advocates say it’s time for New York to take a stand.

"I would argue if we’re going to be a state that really wants to challenge the federal government, this is the area where we should do it because it’s about saving lives," State Senator Gustavo Rivera told Zucker at a budget hearing in Albany on Tuesday.

Zucker confirmed at the hearing that potential legal challenges are a key reason for the delay in approving SIFs in New York. He cited an op-ed in the New York Times in which U.S. Deputy Attorney General Rod Rosenstein emphasized that the facilities are still illegal, and noted that he’s received letters from New York City Special Narcotics Prosecutor Bridget Brennan.

“The push for [injection sites] over-emphasizes harm reduction at the expense of public safety,” she reportedly wrote to state health officials in June.

However, Zucker also said he still isn’t convinced SIFs are beneficial. Existing research, while somewhat limited, suggests that they help prevent overdose deaths and public drug use while providing access to treatment. If allowed to move forward, the proposed sites in New York would also be studied to determine their effectiveness in promoting public health.

Zucker said he is still conducting his own investigation, including talking to officials in Canada, where such programs have been operating for years.

The state Health Department has the authority to authorize supervised injection sites if they’re part of a research study, according to the city. In a letter Deputy Mayor Herminia Palacio sent Zucker asking him to approve the sites last year, she noted that the state health commissioner approved needle exchanges in the same context in the early 1990s.

The state didn’t give a time frame for approving the sites, but it has now been about nine months since the city made the request.

In Pennsylvania, Governor Tom Wolf has also come out against supervised injection sites but, unlike in New York, his office has said he would not get in the way of one opening in the state.

Former Pennsylvania governor Ed Rendell, who is on the board of Safehouse, has taken a much bolder stance. Asked about the potential legal repercussions of being involved with such a project in the past, Rendell hasn’t wavered in his support; he’s even joked about the possibility of spending time behind bars.

"Federal prisons are much nicer than city prisons or state prisons," he told the Philadelphia Inquirer in October. "I'll be happy to go to Allenwood for a month and play tennis."