The US nuclear arsenal remained roughly unchanged in the last year, with the Defense Department maintaining an estimated stockpile of some 4,000 warheads to be delivered via ballistic missiles and aircraft. Most of these warheads are not deployed but stored, and many are destined to be retired. Of the approximately 1,800 warheads that are deployed, roughly 1,650 are on ballistic missiles or at bomber bases in the United States, with another 150 tactical bombs deployed at European bases. Read the Nuclear Notebook in the March/April 2018 issue of the digital Journal. The Nuclear Notebook is always free-access.