Republicans from President Trump on down have sought to define Democrats around proposals to extend Medicare to everybody, and conservative writers and activists have joined the pile on.

This is certainly understandable. Even the liberal Urban Institute has pegged the cost of such a program at a staggering $32 trillion over a decade. Any such plan to migrate everybody over to Medicare would mean massive taxes, cause significant disruption to the industry that’s the largest employer in the U.S., as well as disrupt the healthcare arrangements of hundreds of millions of Americans who are currently satisfied with what they have.