U.S. President-elect Donald Trump has picked Brandon Williams, a former Navy officer and one-term member of Congress, to become the keeper of the nation¡¯s arsenal of thousands of nuclear bombs and warheads.

Trump¡¯s selection is a shift from a tradition in which the people who served as administrator of the National Nuclear Security Administration typically had deep technical roots or experience in the nation¡¯s atomic complex. What¡¯s unknown publicly is the extent of Williams¡¯ experience in the knotty intricacies of how the weapons work and how they are kept reliable for decades without ever being ignited.

Terry C. Wallace Jr., a former director of the Los Alamos weapons laboratory in New Mexico, expressed surprise at Trump¡¯s pick.