On Monday, the U.S. Supreme Court will begin hearing oral arguments over the constitutionality of the Affordable Care Act. Many believe the outcome will be a watershed moment for health reform, and could even affect the November presidential race. Attorneys general from 26 states with Republican-controlled legislatures are suing the federal government to repeal the ACA. At issue is the individual mandate, the requirement that all Americans purchase private health insurance if they aren’t covered through an employer or eligible for Medicare or Medicaid. The opposing states argue that the mandate is an unconstitutional expansion of Congress’ power to regulate the economy. The Obama administration counters that the mandate is necessary to bring everyone into the system so as to prevent taxpayers from being burdened with the hospital costs of those who don’t have insurance. The mandate doesn’t go into effect until 2014, when the state health insurance exchanges are scheduled to start.

However, some single payer advocates, are siding with the ACA’s Republican opponents, arguing that the public shouldn’t be forced to buy private health insurance. Unlike GOP critics who want the ACA replaced with either vouchers or health savings accounts, single payer advocates instead want Medicare immediately expanded to all Americans. Fifty doctors and two non-profit groups – Single Payer Action and It’s Our Economy – have filed a friend-of-the-court brief in favor of striking down the individual mandate.

“It is not necessary to force Americans to buy private health insurance to achieve universal coverage,” said Russell Mokhiber of Single Payer Action. “There is a proven alternative that Congress didn’t seriously consider, and that alternative is a single payer national health insurance system.”

The national arm of the Green Party has also called for the justices to strike down the individual mandate.

“America needs real universal health care, not a direct public subsidy in the form of a health insurance mandate to sustain the private insurance industry,” said Barry Hermanson, Green candidate for Congress in California’s 12th District (San Francisco) (http://www.barryhermanson.org). “President Obama and Democrats in Congress could have introduced a Medicare For All bill, which would cover every American and drastically reduce medical costs by removing insurance companies from control over our health care. Instead they acted in the interests of insurance and other corporate lobbies. Even with the mandate, the ACA leaves 23 million Americans without coverage and many millions more with inadequate health care.”

If the Supreme Court overturns the individual mandate, thus crippling a key provision of the ACA, or strikes down the law entirely, could we see a renewed demand from the public to expand Medicare? Would the United States be forced to adopt single payer sooner rather than later? Single payer advocates who oppose the ACA certainly hope so. It’s possible that the public will give national health insurance another look, especially since Republican alternatives like vouchers and health savings accounts don’t lead to universal coverage and don’t control costs. The cost of health care will continue to spiral out of control. Thousands of people will continue to die prematurely. Thousands more will continue to go bankrupt. This much is clear: expanding Medicare to all doesn’t involve a mandate and threat of a fine. Membership is automatic. Should the ACA be repealed, the case for national health insurance will be stronger than ever and lawmakers will have to listen.