Mr. Sanders — who, of course, isn’t even a registered Democrat — is banging on about what he calls “Medicare for All,” a government-run plan that would provide health care coverage for every American. . . .

A goodly number of those senators are presidential hopefuls, leaving their prospective campaigns open to attack from Republicans salivating to capitalize on an idea that has historically been a political graveyard. Remember Hillarycare?

As a centrist Democrat, I’m scared to see my party pulled into positions that are both bad politics and dubious policy. And I’m disappointed that few of our party’s moderates are willing to resist the freight train coming at us from the left. . . .

Amid the many complications of Medicare for All, the question of what would happen to the 157 million Americans who get their insurance from their employers and the 19 million who are enrolled in Medicare Advantage loom large.