While the Supreme Court considers one challenge to a provision of the Affordable Care Act (ACA), a federal appeals court located just blocks away is contemplating a separate challenge that could have much more dire consequences for the future of the law. […] The conflict at the center of the Halbig (vs. Sebelius) case (and three other challenges across the country) has to do with tax subsidies granted to those who seek to obtain insurance from the exchanges. The ACA grants the credits to qualifying individuals in order to defray the cost of the insurance. Millions of Americans are expected...