The U.S. Navy is sending a 900-foot ship to within about 50 miles of Venezuela, but this isn’t a typical show of strength. The USNS Comfort is a floating hospital, equipped with surgical rooms, a CT scanner and 5,000 units of blood. Its mission is to provide free care, including to Venezuelan refugees fleeing their collapsing socialist homeland.

The Comfort is midway through an 11-week trip to South and Central America. This week the ship was in Turbo, Colombia, where it docked Nov. 14. On Saturday it is scheduled to arrive...