The Supreme Court’s decision in King v. Burwell last week preserved the Affordable Care Act's subsidies for all enrollees, and Chief Justice John Roberts’s vehement dismissal of the plaintiffs’ arguments signals that the Court is averse to further efforts to repeal Obamacare through litigation. The contest over health care reform therefore shifts from the courts back to politics: The ACA likely will be an issue in the 2016 election. But what should be done to improve it?

The ACA has only partially achieved its goals. Its principal goal was to get coverage for uninsured Americans, because the U.S. was facing a crisis: Not only were many Americans uninsured, but also their ranks were steadily growing:

That trend reversed sharply after the ACA passed in 2010. Nevertheless, at least 10 percent of Americans still lack health insurance. It will be difficult to reduce that percentage significantly, as the Supreme Court’s 2012 National Federation of Independent Businesses v. Sebelius decision allowed each state to make its own choice about whether to expand the Medicaid insurance program to make more poor families eligible. Many red states refused the expansion, even though those very states have especially high concentrations of impoverished, uninsured families. Unless those states change their policies, universal coverage will remain elusive.

So, the first piece of the health care reform agenda is clear: Reformers must convince voters, legislators, and governors in those states to expand Medicaid.

The ACA was also designed, in lesser part, to address the growth in health care spending. The U.S. spends far more per person on health care than any other country, while achieving only mediocre results in population health. Again, the problem was getting worse: Our annual increases in health care spending are greater than overall inflation. Unchecked growth in health care spending threatens the fiscal solvency of Medicare, and with it every other governmental function that progressives value.