Document Leaks Indicate Extent of U.S. Electronic Snooping

Updated April 15, 2023 7:53 am ET

WASHINGTON—The classified documents that investigators say were leaked by a junior member of the Massachusetts Air National Guard indicate the extent to which U.S. spy agencies rely on clandestinely intercepted communications to keep tabs on their adversaries and allies alike.

In vivid examples, the documents track foreign governments’ military movements, diplomatic efforts and clandestine weapons sales, as well as debates in friendly capitals and…