News arrived last week that Our Revolution, the political group that arose from Bernie Sanders’s presidential campaign, is going to back primary challenges against Democrats who aren’t deemed ardent enough in their support for single-payer health care. “We’re not going to accept no more hemming and hawing,” said the group’s president, Nina Turner. “Make your stand.”

This makes for a potentially fateful moment — in the history of the Democratic Party, and in the history of our ever more polarized politics. It’s also, as alluring as such uncompromising passion can sound, very substantively misleading.

If you’re a normal person who doesn’t have much time to burrow into the details of policy, you can be forgiven for thinking that the health care choice we face in this country is between the current improving but still inefficient and dissatisfying status quo and a single-payer system. After all, single payer, in which the federal government acts as every American’s insurance provider, is the only alternative that ever gets discussed.

But that isn’t the case. Single payer is a policy choice, not a principle. The principle is universal coverage. Single payer is one way to get there. It’s how Britain and Canada do it. But there are other ways. France uses a hybrid system that is mostly but not wholly single payer. Germany uses private insurers, mostly nonprofit, but gives the government more control over how they operate. In Japan, private insurance supplements a government-run basic insurance program.