A new Trump administration court challenge is explicitly aiming to remove a central promise of Obamacare — its protections for people with preexisting health conditions. But if the court rules in the way the Justice Department has requested, the result will be a world in which it is much more difficult for individuals and small businesses to buy health insurance. The health law is complicated, with interlocking parts. It will be hard to remove just two rules from the individual market without disrupting many others. (New York Times by Margot Sanger)