Presidential hopefuls have their own ideas on what to do with the Affordable Care Act (ACA), President Obama’s signature legislation, when they move into the White House.

Sen. Bernie Sanders thinks it should be replaced with a single-payer health plan of the kind Europe and Canada have. This federally administered universal health care program would eliminate copays and deductibles. There’s currently a move afoot in Colorado to have such a plan.

Secretary Hillary Clinton would like to keep the ACA, with a few fixes.

Donald Trump says he will uproot the ACA, get Congress to allow the sale of health insurance across state lines and allow individuals to take tax deductions for insurance premium payments. But that would not help low-income Americans because they do not pay much in income taxes.

This week, the American Journal of Public Health carried a proposal by a working group of more than 2,000 physicians nationwide titled: Moving Forward from the Affordable Care Act to a Single-Payer system. The physicans warn that the risks of continuing the ACA will leave millions uninsured indefinitely.

NAM health editor Viji Sundaram interviewed Dr. Adam Gaffney, a co-chair of the working group.

Viji Sundaram: Your proposal calls for a single-payer health care plan for the United States. Obamacare has helped 16.9 million people become newly insured. Would it not be less disruptive to expand the provisions in the ACA instead of repealing the law and replacing it?

Dr. Adam Gaffney: The U.S. health system is highly disruptive as things stand now. You’re liable to lose your insurance at any time—for instance, if you change your job or get divorced. Similarly, those purchasing plans on the “marketplaces” may find that they can keep down premium increases by changing plans on an annual basis. Every time your insurance plan changes, you may need to change all of your doctors and hospitals in order to stay “in network.” This is enormously disruptive to people’s health care. In contrast, in a single-payer system, everyone has free choice of doctors and hospitals.

VS: Your proposal promises health coverage for all. Does this include undocumented U.S. residents?

AG: Yes, it would. The single-payer national health program we envision would include everyone regardless of country of origin, including undocumented residents. If we believe that health care is truly a human right, then this is the right thing to do. At the same time, it is also financially achievable. Immigrants, on average, have lower health care spending as compared to those born in the United States. One study demonstrated that immigrants actually pay more into Medicare than what they use in terms of health care. Everyone would be included in the national health program we envision.

VS: Why do you think there would be no additional government spending if the United States has a single-payer health care plan? Countries such as Canada and the England run their national health program on the backs of taxpayers. Will that happen in the United States as well? Can it be done without raising taxes?

AG: There would be additional government spending with a single-payer plan, but this would be offset by the elimination of spending by individuals and employers on premiums, co-payments, and deductibles. We can expand coverage to everyone in the country and eliminate co-payments and deductibles, and at the same time keep overall current health care spending roughly unchanged.

VS: Some providers criticize single-payer plan as one that will force them to contract with the one payer available. Currently, providers have some choice of insurers. They can even opt out of Medicare and Medicaid.

AG: There are many benefits for practices to have to contract with only one payer: it’s much simpler and is less costly from an administrative perspective.

VS: How would you respond to the criticism of the single payer program as having the capacity to get doctors to sign in with fairly attractive reimbursement rates, but once in, those rates can come down, leaving providers helpless?

AG: Because the vast majority of the nation’s doctors would participate in the national health program, there would be a powerful lobby fighting to ensure that reimbursements remain fair.

VS: In countries that have a single-payer health care system, there seems to be a long waiting period before a patient can see a doctor. How can we keep that from happening in this country?

AG: The problem of waiting times for care in other nations is often exaggerated. Moreover, where there are excessive waiting times for elective procedures, it is often due to underinvestment. We spend much more than other countries on health care, and have the resources to ensure that waiting times for elective procedures are reasonable. It’s also worth noting that we have waiting times in the United States also, though they are not as visible. Indeed, if you have the wrong insurance plan [currently], the waiting time for some providers may, so to speak, be infinite.

VS: The UK allows people to be in both the national health plan as well as subscribe to a private insurance plan, which they can fall back on for expedited care. But your plan calls for an end to commercial insurance.

AG: First, if providers must bill and contend with multiple different insurance plans, we lose the efficiency savings that come with a single universal system. Second, if we give the rich preferential access to superior and expedited care while relegating everyone else to an inferior tier, we make a mockery of the idea of an equal right to health care. Third, the best way to ensure that the quality of health care is superb is having everybody—whether rich or poor—in the same system together.

VS: Medicaid and Medicare depend on the cost shift from private payers. Some providers say the only way doctors are willing to get into the Medicare network is because they get higher payment from commercial insurers.

AG: Doctors would continue to do well under a Medicare-for-All system. The transition to a single-payer system would eliminate the need to bill and contend with a multiplicity of payers, producing substantial savings for practices (and hospitals).

VS: How much could the United States save by switching to a single-payer health plan? What does it currently spend?

AG: It is estimated that upwards of $400 billion a year could be saved from reduced spending on administration and billing that would occur through the transition to a single-payer plan. Additional money could be saved when the national health program enters into direct negotiations with pharmaceutical companies over drug prices. These savings could then be used to cover everybody in the country, while at the same time eliminating copayments and deductibles. Overall health care spending, at the end of the day, would be approximately the same as it is now, but nobody would ever again have to worry about losing insurance, about paying a big deductible if they got sick, or about not having access to the doctor or hospital of their choose.