Adam Gaffney is an Instructor in medicine at Harvard Medical School and a pulmonary and critical care physician at the Cambridge Health Alliance and serves on the board of directors of Physicians for a National Health Program.

People in California rally for single-payer. (AFP)

Single-payer universal health care — once cast as a radical daydream — has moved with staggering swiftness from purported fantasy to palpable possibility. Today, Sen. Bernie Sanders (I-Vt.) released his long-awaited single-payer bill, and a slew of senators now numbering in the double digits have announced their support. This bill will serve as a potent Senate counterpart to Rep. John Conyers Jr.’s (D-Mich.) single-payer bill, now co-sponsored by 117 representatives — a historic and unprecedented majority of House Democrats.  Far from being an impossibility, the idea that we might create a right to health care is starting to feel like an inevitability.

Just last week none other than former senator Max Baucus — a central player in drafting the Affordable Care Act and a previous foe of single-payer reform — embraced single-payer as the next step. As Baucus, quoted by the Bozeman Daily Chronicle, put it: “It’s going to happen.”

But is it? Probably not tomorrow. The regressive right-wing government that recently came within a hair’s breadth of repealing the ACA and gutting the existing health-care safety net — an undertaking it could attempt again — is rather unlikely to pass sweeping single-payer legislation anytime soon. So why do bills like this one deserve any attention?

For one reason: because aspirations structure reality.  And also because this political epoch will end, and with it the intensely unpopular presidency of Donald Trump, which will one day be a distasteful memory. Political change will thus invariably — even if only for a while — make transformative reform possible. And when it does, bills like that of Conyers and Sanders might move from ambition to achievement at a hurried pace.

This has happened before. Shortly after World War II, in 1945, the British Labour Party won a historic parliamentary victory, a contest tantamount to a mandate for a new Britain in which — as historian Donald Sassoon has written — the “citizenship rights which had been the rallying cry of the liberal-democratic condition … would be supplemented by new socio-economic rights” — including the right to health care. The following year, the Labor Parliament passed the National Health Service Act, and two years after that, the National Health Service went into operation: Everyone in that nation thereafter gained access to free, comprehensive health care — an advance that can be described without hyperbole as a civilizational breakthrough.

Circumstances there were, of course, unique. Could something similar happen in the United States? It could — and it has. In 1964, Democrats swept the congressional elections, and the following year, Lyndon B. Johnson signed Medicare and Medicaid into law.  Implementation of Medicare was even more rapid than that of the NHS: Within a year of the law’s signing, 99 percent of the nation’s seniors were enrolled in the universal part of the program.

There is simply no good reason (much less some titanium law of nature) that precludes us from universally expanding Medicare today, which is precisely what some of its architects had in mind decades ago. Nor must this necessarily hinge on some historic electoral sweep: As Baucus’s astonishing single-payer turn demonstrates, when activists transform the narrative around an issue — when they push a policy to center-stage — smart politicians will follow.

Feasibility, of course, is a separate issue from desirability — and what Americans desire is what is quickly changing, as our values evolve.

The gaps in the U.S. health-care system are simply too large to be plugged by the half-measures on offer. Even with the ACA, 28 million — or nearly 9 percent of the nation — remains uninsured. Single-payer would fix that, but covering the uninsured is far from its only goal: What single-payer is uniquely well-suited to do is reduce inequalities imposed by income, race, gender and a host of other factors.

Economic inequality and health inequality are deeply interwoven in 21st-century America. It was for a good and humane reason that the architects of the NHS — like the designers of the Canadian public health-care system — envisioned a universal program with “no charges, except for a few special items,” as an explanatory leaflet sent to each and every residence in Britain shortly before the launch of the service put it.  By covering everyone, while also eliminating co-payments and deductibles — as both bills prudently do (with the exception of prescription drugs in the Sanders’ bill) — we ensure that all receive care depending of their health needs, not their wealth.

But there are also some particularly American health-care inequalities — in race and gender — that must be addressed, and that single-payer could do much to diminish. For instance, today, Hispanics and blacks remain uninsured at substantially higher rates than whites. Moreover, it seems likely that racial minorities — in light of vastly lower average household wealth — are also harder pressed, dollar for dollar, by deductibles or co-payments, as noted in the Harvard Public Health Review.

And additionally, for all the enormous good done by Medicaid, its lower rates of provider payments sometimes contribute to a lower level of accesslonger waits for appointments, and — in some instances — effective health-care segregation for the program’s mostly minority participants. Such inequities could be mitigated with a truly universal, single-tier program.

Then there are gender inequalities, namely inadequate access to reproductive health care, especially abortion. Admittedly, a number of policy reforms are needed in this area, but single-payer could make an enormous difference. For a variety of reasons, even insured women can face major barriers in obtaining abortions, and very infrequently rely on private insurance: In 2008, a mere 12 percent of women obtaining an abortion used private insurance to cover the cost, according to the pro-choice Guttmacher Institute. A single-payer program that included access to comprehensive reproductive health care while overriding Hyde — as Sanders’ bill appears to do — would represent an important step toward greater gender equity in health care.

Thus, taken together, the raison d’etre of single-payer reform, are primarily ethical, and only secondarily economic.  Indeed, rising support for single-payer should be seen as part of a larger shift toward more egalitarian values on  a host of social and economic issues in America, including on gender and racial equity. At single-payer’s core is the age-old principle of basic human equality, translated to the arena of health. “Health care is a basic human right,” Sen. Elizabeth Warren wrote in an email to her supporters (quoted in Vox) announcing her support of Sanders’ bill, “and it’s time to fight for it.”

The movement for universal health care is, of course, an old one, with many defeats in the past. “Our new Economic Bill of Rights,” Harry S. Truman once said while advocating for a national health insurance program shortly after World War II, “should mean health security for all, regardless of residence, station, or race — everywhere in the United States.” But while Cold War-era scare tactics doomed that effort, they need not sink this one. The sheer popularity of single-payer (53 percent of Americans favor it) and the number of serious politicians now behind it show that we’re changing as a country — for the better.

Sen. Bernie Sanders (I-Vt.) introduced his "Medicare for All" plan to provide universal health coverage to all Americans on Sept. 13. The bill has 16 Democratic co-sponsors. (Reuters)