"Our adversaries are persistent, and they are sophisticated. ... China is the most persistent threat, while Russia has gained significant capabilities through their ongoing operations," said Lt. Gen. William Hartman, acting commander of U.S. Cyber Command and acting National Security Agency director. His remarks came as he appeared before the Senate Armed Services Subcommittee on Cybersecurity to testify on national security and the U.S. cyber defense posture. Several topics were addressed, including cyber workforce challenges, benefits to his "dual hat" role leading both Cyber Command and the NSA, improving the cyber deterrence framework, challenges posed by adversaries, and the implementation of artificial intelligence (AI).