A 35-year-old Washington, D.C., man visited an urgent care clinic on Jan. 19, a few days after returning from Wuhan, China. After undergoing testing, the Centers for Disease Control and Prevention determined that he had contracted the 2019-nCoV coronavirus—the first such case in the United States. Since surfacing in Wuhan in December, the 2019-nCoV coronavirus has spread to nearly 30 countries, killing 565 and infecting more than 28,000 worldwide. As of this writing, 12 cases have been confirmed in the U.S. Note that these numbers are changing almost every hour. As cases began to emerge within American borders, the Trump...