The special counsel, Robert Mueller, has followed a set of rules devised to allow for the investigation of a sitting president. Those rules will now be tested. Guests: Neal Katyal, who drafted the regulations that govern Mr. Mueller\u2019s investigation, and Michael S. Schmidt, who has been covering the special counsel investigation for The New York Times. For more information on today\u2019s episode, visit nytimes.com/thedaily.