November 6 was a big night for President Barack Obama, giving him a decisive win for a second term. The evening brought wins to scores of House and Senate candidates and to state initiatives, including the legalization of gay marriage in Maryland, Maine, and Washington.

Another big winner that night was the Affordable Care Act. Former Massachusetts Gov. Mitt Romney had pledged to repeal the law and let states go forward with their own reforms. Dismantling a law as complex as the ACA ...