After a bruising midterm election in which widespread insecurity over the future of health care helped Democrats retake the House of Representatives, the Trump administration decided it would not defend the Affordable Care Act in a case that could end in the wholesale invalidation of the Obama-era health law. Ever since the Affordable Care Act was passed in March of 2010, Republicans have been working to repeal the law, without a clear plan to replace it, a move that would leave tens of milli...