There’s an old joke that Canadians like to tell: What’s a Canadian? A gunless American with health care.

It’s only funny because we half-believe it’s true; despite the many things we have in common with our friends south of the 49^th parallel, Canada’s single-tier, publicly funded health care system has long been a point of differentiation—and pride—for most Canadians. A 2012 poll found that our health care system—known in Canada as “Medicare”—was almost universally loved, with 94% of those surveyed calling it an important source of collective pride. The notion that access to health care should be based only on need is a deeply ingrained Canadian value.

But we can’t take our Medicare system for granted.

The challenges to Canadian Medicare have always been ideological and political. But, as of this month, they are also legal.

In the western province of British Columbia, a trial underway in that province’s Supreme Court is challenging the very foundations of Medicare: providing care based solely on need, and not on ability to pay.

Cambie Surgeries Corporation and the Specialist Referral Clinic, represented by Dr. Brian Day, an orthopedic surgeon in Vancouver, are suing the government of B.C., trying to knock down the laws that protect our single-payer system. If successful, some Canadians will be able to pay out-of-pocket or through private insurance for hospital and physician services—and doctors will be able to charge them whatever the market will bear.

In British Columbia, as in all Canadian provinces, “Medicare” provides public funding for all medically necessary hospital and physician services to all legal residents. Core to the system are some key restrictions on physician behavior.

Let’s say you come to see me in my office about a rash, or a possible pneumonia, or diabetes. I would talk to you, examine you, perhaps propose some laboratory tests, perhaps write you a prescription. The public insurance plan in my province would pay me for that 15-minute visit, let’s say $50. As a Canadian physician choosing to be enrolled in Medicare, I bill the government that $50, but I am not permitted to then bill you an additional $20—meaning copayments, or “extra billing,” is not allowed. In other words, Canadian doctors who bill the public insurance plan may not bill patients at all.

These restrictions on dual practice and extra-billing, coupled with B.C.’s ban on any private insurance that duplicates Medicare coverage, are the targets of the court challenge currently being brought forth by Dr. Day’s private for-profit, investor-owned surgical clinic.

The essence of the claim is that, because wait times for some elective surgeries in that province are longer than we would like them to be, doctors should have a constitutionally protected right to provide them more quickly and at a higher price. This would be done by charging some patients privately, either out-of-pocket or through private insurance. They allege that existing limits on charging patients privately infringe on patients’ rights to life, liberty, and security of the person under Section 7 of the Canadian Charter of Rights and Freedoms.

This legal challenge emerged in response to an audit of Cambie Surgeries Corporation, which was carried out after patients complained to the B.C. government that they were being charged out-of-pocket for care. From a sample of Cambie’s billings, the auditors found that patients had been charged hundreds of thousands of dollars for health services already covered by Medicare. Championed by Dr. Day, Cambie Surgeries Corporation and the Specialist Referral Clinic then countered that the law preventing a doctor from charging patients more than the agreed upon fee schedule is unconstitutional—and a challenge to Canada’s Charter of Rights and Freedoms was born.

The opening statements, which began on September 6, 2016, are behind us now, but Canadians are following the case—expected to last at least 24 weeks—in the popular press, as Cambie’s lawyers try to paint a pretty dark picture of our health-care system. This, in spite of the fact that our outcomes are comparable to those in the United States and are achieved at a fraction of the price.

Meanwhile, the Attorneys General of B.C. and of the Government of Canada are countering that a multi-payer health care system would lure physicians from the public-pay sector to the private-pay sector, potentially reducing the availability, quality, and timeliness of care in the publicly funded system. Both governments will also argue that such a multi-payer health care system will drive up costs, forcing the public single payer to pay higher fees in order to “compete” with private insurers.

It is also worth noting recent efforts at tackling the main driver of this constitutional challenge: wait times for non-urgent surgery. These have come from within the public system, and include wait time targets, centralized intake for people with a common problem, and inter-professional health-care teams so that surgeons’ time does not create a bottleneck. Such initiatives show tremendous promise for reducing waits deemed unreasonable, but governments need to implement them, and health-care organizations and doctors need to help accelerate this kind of reform.

Whatever the decision of the trial judge in B.C., it is likely to be appealed to the Supreme Court of Canada. The foundational pillar of Canadian Medicare—equitable access to health care for all—could well be threatened from coast to coast to coast by the outcome of this decision.

It may be that the Cambie plaintiffs will be unsuccessful in their quest to dismantle the essence of Medicare, but clearly the stakes for ordinary Canadians are very high. Like all developed countries, Canada struggles to control growth in health-care costs, meet the needs of an aging population, and provide timely care of the highest standard. Whether we continue to work to do so for all Canadians, or only some, will, in part, be determined by the outcome of the Cambie case.