"I greatly appreciate Melissa Hathaway's service and her dedication to ensuring the security of our nation's cyber infrastructure," Langevin said. "She has helped us make significant progress towards that goal, and I wish her the best in the future." He added that several months have passed since Hathaway completed the administration's cybersecurity review and he is hopeful President Obama will appoint a cyber coordinator soon. In May, Obama vowed to handpick such an official who would report to the National Security Council and National Economic Council.

McCaul called Hathaway's departure "a loss to our efforts to better protect our nation's cyber networks." "I hope the administration will proceed with deliberate speed to fill this important position," he said. Langevin and McCaul also served as co-chairs of the Center for Strategic and International Studies' Commission on Cybersecurity for the 44th Presidency. That panel's report informed much of Hathaway's deliberations and spurred several hearings on Capitol Hill. Read more congressional reaction to Hathaway's resignation in CongressDaily's PM Edition here (subscription required).