Former senior defense officials issued stark warnings to lawmakers Thursday about intensifying threats posed by unattributed drone incursions and unidentified aerial phenomena (UAP) reported around the U.S. — particularly over military bases, assets, and nuclear facilities. “I don’t think the public is aware of the extent of our airspace vulnerabilities and failures, and the degree to which they’ve already been exploited and are being exploited today, and the challenge that we face in trying to sort this out,” Christopher Mellon, the former deputy assistant secretary of defense for intelligence, said during an event hosted on Capitol Hill by the UAP...