As the Democratic presidential primary race tightens to a virtual tie nationally, the debate over single-payer health care is growing increasingly tense — and consequential.

In the past several weeks, Hillary Clinton and a host of pundits and policy wonks have articulated an evolving set of arguments about why “Medicare for All” is not affordable, achievable, or worth the effort. A number of rejoinders have made the case that it is, on the contrary, all of these things. More recently, a new line has emerged: yes, current reforms fall short of universal health care, but no, single-payer isn’t necessary to achieve it.

Clinton argued as much at the most recent debate: “I don’t want us to start over again . . . I want to build on the progress we’ve made. Go from 90 percent coverage to 100 percent coverage.” Scott Lemieux outlined a similar vision in a Guardian article last Friday headlined “Americans don’t need single payer healthcare to get universal coverage.” “Single payer healthcare,” Lemieux writes, is not interchangeable with “European-style healthcare.”