A special Customs and Border Protection unit used sensitive government databases intended to track terrorists to investigate as many as 20 U.S.-based journalists, including a Pulitzer Prize-winning Associated Press reporter, according to a federal watchdog. Yahoo News, which published an extensive report on the investigation, also found that the unit, the Counter Network Division, queried records of congressional staffers and perhaps members of Congress. Jeffrey Rambo, an agent who acknowledged running checks on journalists in 2017, told federal investigators the practice is routine. “When a name comes across your desk you run it through every system you have access too,...