Bernie Sanders released an updated plan last week to pay for Medicare for All. The plan is light on details, but leaves the senator at least $12.5 trillion short of covering the cost of his health-care proposal over 10 years. It calls for some tax increases on working families, but the real burden may be much higher than advertised: Mr. Sanders may have to raise taxes on American workers by 16 percentage points or more to avoid multitrillion-dollar deficits. Fortunately, Elizabeth Warren’s financing plan for Medicare for All offers a better alternative.

Mr....