Just hours after a panel the D.C. Circuit held (over a dissent) that the ACA could be read just one way — to forbid health-care premium subsidies in health-care exchanges run by the federal government rather than a state — a panel of the Fourth Circuit (which covers the states of Maryland, Virginia, West Virginia, North Carolina and South Carolina) went the other way. That court held that the ACA was ambiguous regarding subsidies for individuals participating in federally-run exchanges, and that the IRS's interpretation permitting subsidies for such individuals was reasonable and therefore entitled to deference from the courts.
Here's the Post story on the division of opinion and its implications. In short: the government insists nothing will change in the short term, partisans on both sides reacted in the ways one might expect based on their support for the underlying law, and the question seems quite likely to be litigated further in en banc proceedings and/or the Supreme Court.