The U.S. Navy announced an “operational pause” and has begun a broad investigation after the destroyer USS John S. McCain collided with a merchant vessel, leaving 10 sailors still missing, the second such incident in as many months. The response by the U.S. military signals the Navy believes it needs to examine whether there may be institutional problems behind the deadly collisions. Navy Adm. John Richardson, the chief of naval operations, made the announcement about the operational pause during a nearly four-minute video message posted on Facebook Monday morning. Adm. Richardson said he also ordered a broader investigation. “I directed...