One tiny sliver of the healthcare industry just gave us a preview of how big of a fight Medicare for All is likely to be. The dialysis industry just spent $111 million in California to defeat a ballot measure that would have limited its profits.

Proposition 8 was sponsored by the Service Employees International Union, which is attempting to organize the workers in dialysis clinics. It would have created incentives for the clinics to hire more care staff and pay them better in addition to capping the revenue of the for-profit clinics. It would have required the clinics to refund insurers any profits over 115 percent of the cost of direct care of patients. It went down by a nearly two-thirds margin after all that money, "national, historical record" setting level of spending for a ballot initiative, was poured in against it.

The industry argued that the measure would cause clinics to close. The SEIU argued that it would put patients first by forcing clinics to accept all patients and providing more trained staff.

The SEIU vows to keep up the fight in California in the legislature and in more states in 2020. Dave Regan, president of SEIU-UHW told the Washington Post's Paulina Firozi that, on average, one dialysis treatment for a Medicare patient in California costs $250 while private insurance can be charged $1,000 or more per treatment. "Dialysis is an outlier within the health-care landscape of a service with a horrible business model, gouging consumers and patients, and it's just a predatory business and it needs to be reformed," Regan said.

The industry promises to stay in the fight, because of course it does. It's insanely profitable, obscenely so. The main two for-profit providers—DaVita and Fresenius—make $3 billion a year in California, alone.

This is a just preview of the fight we're going to have in Medicare for All, while at the same time a stunning indictment of the for-profit healthcare system in the U.S. The fight against Prop 8 wasn't about patient care. It was about shareholder and CEO compensation. That's what we're going to be up against in the years to come as Medicare for All gains steam.