If Democrats take back Congress and the White House on a pledge to enact single-payer, they would find themselves in a similar predicament. While expectations of the progressive base would run high, the simplistic talking points of the campaign would run smack into the realities of health-care policy.

Democrats would not be able to quickly ram through the existing House “Medicare for All” legislation, which is a wisp-thin, not-ready-for-prime-time 30 pages long. And digging into the details would not be pretty.

Already we’ve seen single-payer pushes founder in deep blue Vermont and California because the upfront costs were steep and few were willing to support the necessary tax increases. The controversial line that greased passage of the Affordable Care Act – “If you like your health care plan, you can keep it” – would be non-operative in a single-payer debate; people currently satisfied with their health insurance would instead be told they would have to give it up for a government plan. The insurance industry would be literally fighting for its life, and would spend millions stoking every possible concern anyone could have about a wholesale revision of one-sixth of the United States economy.