Air Force Gen. Timothy D. Haugh took the helm of the National Security Agency and the Cyber Command on Friday, as the intelligence agencies and military brace for renewed efforts by foreign adversaries to influence the American elections this year. General Haugh replaces Army Gen. Paul M. Nakasone, who took over in 2018 and helped focus the N.S.A. and Cyber Command on countering foreign efforts to interfere in American elections. The N.S.A. collects communications intelligence, like phone calls and computer traffic, and Cyber Command conducts operations on computer networks. Securing…