On Wednesday Sen. Bernie Sanders (Socialist, Vt.) rolled out this year’s version of his draft legislation to abolish traditional Medicare. He calls it “Medicare for All” because polls tell him that voters don’t want to abolish traditional Medicare. Voters also don’t want him to destroy the U.S. system of private medical insurance, but his plan would do that, too. A key question raised by the new bill is whether patients, doctors and nurses would be able to escape the new government-run system when it fails to provide needed care—as such systems always do. Calling it “Medicare for All” is not...