Recently, two federal courts came to opposite conclusions about the Affordable Care Act’s tax subsidies to help people pay for health insurance. At issue was an IRS regulation that interprets the law to mean that subsidies should be available in all states, not just ones that run their own insurance marketplaces. In a new blog post, Sara Rosenbaum of the Milken Institute School of Public Health at the George Washington University explains what's at stake for millions of Americans.