This Viewpoint discusses 4 key changes that could improve the Affordable Care Act and create broad support across the states.

The Affordable Care Act (ACA) is best seen as transitional legislation on the road to long-term structural reform of the US health care system. This is not so much because the ACA is politically controversial and there is bound to be pressure for changes, despite the US Supreme Court’s King v Burwell decision,1 but rather it is because the ACA’s design still lacks the consistent, strategic building blocks needed for a stable, long-term system redesign.