In June, the director of National Intelligence and the Secretary of Defense are expected to deliver a report about what the government knows on the subject of “unidentified aerial phenomena,” more commonly known as U.F.O.s. The issue is nonpartisan: while he was the Senate Majority Leader, Harry Reid, a Democrat, secured funding for a secret Pentagon project to investigate the subject; John Podesta, a chief of staff in the Clinton White House, argued for government transparency on the topic; most recently, the Republican senator Marco Rubio introduced language in last year’s Intelligence Authorization Act calling for the forthcoming report. This is a shocking turn of events. For generations, U.F.O.s were in the purview of late-night call-in radio shows and supermarket tabloids, not the Department of Defense. Gideon Lewis-Kraus reports on how this change came about. The journalist Leslie Kean, who published a bombshell story in the New York Times, explains how the C.I.A. got involved in casting doubt on U.F.O. sightings. Reid tells Lewis-Kraus that the Pentagon refused to authorize his inspection of contractor facilities which, it was rumored, held U.F.O. crash debris. And a former Deputy Assistant Secretary of Defense, Christopher Mellon, says that the phenomena observed in many sightings cannot be explained as advanced technology built by one of our rivals. “I really doubt that the Russians or Chinese could be that far ahead of us,” he says. “It looks like centuries ahead.” So, whereas the word “aliens” still seems like taboo in serious conversation, he adds, “it's hard to come up with a hypothesis to explain that without considering the possibility that some other civilization is involved.” Gideon Lewis-Kraus’s “How the Pentagon Started Taking U.F.O.s Seriously” appears in the May 10th issue of The New Yorker. This segment features scoring by Pablo Vergara. Additional archival clips were provided courtesy of James Fox.