For instance, according to the latest estimates from the National Center for Health Statistics, some 29 million people were uninsured in 2015. Covering these individuals requires cash. It’s worth pointing out, however, that many of these individuals are already using health care, with some of the costs either coming out of their own pockets or being passed on to other public or private payers. Replacing those existing expenditures will have zero effect on overall national health spending. At the same time, many of these individuals are, sadly, currently forgoing health care, and to the extent that universal health care allows them to go to the doctor or get tests or medicines they’ve so far been avoiding, some new money will indeed need to be spent.

Second, proposals for “Medicare-for-all” usually call for the elimination of cost sharing, which is to say no copayments, deductibles, and co-insurance. I’d argue that this is an essential aspect of real universal health care (with some notable exceptions, such payments are absent from the systems of Canada and the United Kingdom). The harms of such payments are all too real: As a result of out-of-pocket exposure, an analysis of survey findings published by the Commonwealth Fund last year put the number of underinsured Americans—the insured who lack sufficient coverage against the cost of medical care—at 31 million in 2014. Though discarding such out-of-pocket payments might sound like a pricey proposition, to the extent that these monies are already being spent, their elimination would be a wash, with no net effect on overall national health expenditures. But again, as is the case with the uninsured, insofar as some individuals and families are avoiding health care because of out-of-pocket payments, the elimination of these financial barriers would result in some real increases in health care utilization.

There are some other points to be made (like the additional costs of providing universal long term care and dental care), but in reality these two items—covering the uninsured and improving coverage for the underinsured—are the main new costs that a single-payer national health program would have to cover. Taking that into consideration, is single-payer indeed “unaffordable”?

To answer, we have to look at the opposite side of the equation, at the potential for efficiency savings in such a transition. And clearly, the biggest source of savings is the reduction of the vast bureaucratic apparatus that undergirds the entirety of the health care system, as Himmelstein and Woolhandler emphasize (and have studied in depth). This “apparatus” is devoted to such critical tasks as the compilation of lengthy itemized hospital bills, the pursuit of medical debtors, the design of needlessly complex yet shoddy insurance products, the issuance of bills to innumerable payers, the endless clinical documentation necessary to generate proper payment from insurers, and so forth. Overall, this represents a massive, parasitic drain on the American economy. And so, too, does our unnecessarily high pharmaceutical expenditures. But it is, in particular, the issue of administrative savings that has received insufficient attention in discussions on health care reform.