Attorney General William P. Barr declared on Monday that a deadly shooting last month at a naval air station in Pensacola, Fla., was an act of terrorism, and he asked Apple in an unusually high-profile request to provide access to two phones used by the gunman.Mr. Barr’s appeal was an escalation of a continuing fight between the Justice Department and Apple pitting personal privacy against public safety. “This situation perfectly illustrates why it is critical that the public be able to get access to digital evidence,” Mr. Barr said, calling on technology companies to find a solution and complaining that...