The Supreme Court of Canada on Thursday began hearing the Canadian government’s case against Insite, a Vancouver-based legal injection site where people can obtain clean needles and syringes to inject their own drugs under a nurse’s supervision, the Canadian Press reports. Proponents of the program say it “prevents overdose deaths, reduces the spread of HIV and hepatitis, and curbs crime and open drug use” (5/12).

Those defending the facility argue that it provides “a form of health care, and that health care is a provincial matter under Canada’s constitution. The federal government counters that its writ trumps provincial rights because heroin is a federally banned substance,” the Associated Press writes (5/11). The court is tasked with determining “whether federal drug laws or provincial health care interests have power over Insite and whether it would violate the Charter rights of drug users to shut it down. One of the government’s core arguments is that public safety is just as important as public health,” according to The Province (Ross, 5/12).

Vancouver Mayor Gregor Robertson and five former mayors on Tuesday sent a letter to the federal government supporting the continued operation of Insite, the Vancouver Sun reports (Lee/Tibbetts, 5/11).