Doctors would have to transition. Salary losses would differ by specialty, but imagine you came out of med school saddled with debt and learn that your payments are going to be down by, say 30 percent. Similar shocks would ripple to other health care workers.

The American people would have to transition. Americans are more decentralized, diverse and individualistic than people in the nations with single-payer systems. They are more suspicious of centralized government and tend to dislike higher taxes.

The Sanders plan would increase federal spending by about $32.6 trillion over its first 10 years, according to a Mercatus Center study that Blahous led. Compare that with the Congressional Budget Office’s projection for the entire 2019 fiscal year budget, $4.4 trillion. That kind of sticker shock is why a plan for single-payer in Vermont collapsed in 2014 and why Colorado voters overwhelmingly rejected one in 2016. It’s why legislators in California killed one. In this plan, the taxes are upfront, the purported savings are down the line.

Once they learn that Medicare for all would eliminate private insurance and raise taxes, only 37 percent of Americans support it, according to a Kaiser Family Foundation survey. In 2010, Republicans scored an enormous electoral victory because voters feared that the government was taking over their health care, even though Obamacare really didn’t. Now, under Medicare for all, it really would. This seems like an excellent way to re-elect Donald Trump.

The government would also have to transition. Medicare for all works only if politicians ruthlessly enforce those spending cuts. But in our system of government, members of Congress are terrible at fiscal discipline. They are quick to cater to special interest groups, terrible at saying no. To make single-payer really work, we’d probably have to scrap the U.S. Congress and move to a more centralized parliamentary system.

Finally, patient expectations would have to transition. Today, getting a doctor’s appointment is annoying but not onerous. In Canada, the median wait time between seeing a general practitioner and a specialist is 8.7 weeks; between a G.P. referral and an orthopedic surgeon, it’s nine months. That would take some adjusting.

If America were a blank slate, Medicare for all would be a plausible policy, but we are not a blank slate. At this point, the easiest way to get to a single-payer system would probably be to go back to 1776 and undo that whole American Revolution thing.

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