He argues that his system will be cheaper than private insurance because it will cut down on "overhead, administrative costs and complexity." But a lot of private insurers' costs come from scrutinizing claims to prevent fraud, over treatment and unnecessary treatment. Agreeing to pay all charges without review, as Sanders proposes, is an invitation to be fleeced.

One reason he thinks the single-payer approach will work so well is that countries like Canada and Britain use it and spend far less than we do on health care. He takes care not to mention one major tool they use to hold down costs: limiting access to procedures that insured Americans take for granted.

"One in four Canadians reported waiting four months or more for elective surgery, similar to the proportion of patients in the United Kingdom (21 percent) but much higher than in Germany (almost 0 percent) and the United States (7 percent)," the Canadian Institute for Health Information found in 2012. One in 5 Canadians needing knee or hip replacements has to wait more than six months.

The Guardian newspaper reported in 2012 that Britain's National Health Service "has come under growing criticism for making it harder for patients to have operations for routine conditions such as hernia, cataracts, grommets, wisdom teeth, or hip or knee replacement, and denying infertile couples IVF."