The Affordable Care Act/Obamacare provides for certain tax breaks to individuals in the state insurance exchanges.
The problem then becomes what to do if a state declines to set up such exchanges.
Despite the fact that there is no provision in the law for doing so, the IRS has apparently unilaterally decided to extend those tax breaks anyway.
Of course, the fact that the IRS has no statutory authority for such a move has held them up a bit.
Rule of law, my ass.