Michael Hayden, a former director of the NSA and the CIA, on Friday called Russia's interference in the 2016 presidential election the "most successful covert influence operation in history." "Frankly, [the Russian meddling] is the most successful covert operation in history," Hayden told a national security panel in response to a question from moderator Yahoo News Chief Investigative Correspondent Michael Isikoff. Hayden said the original cyberattack on the Democratic National Committee was not that surprising -- and even from an intelligence perspective, impressive. "I just have to admit as a former director of NSA, [Russia's hack and theft of email]...