The Nuclear Posture review is out in public and it moves US nuclear weapons from a strictly “deterrent” role (Don’t you dare use yours or we will devastate you) to possible other roles. Throughout the first cold war deterrence was the only legal role of US WMD’s and the American public as well as Congress was sold the massive nuclear arsenal on that premise. Together with the Trump administration’s even larger ($1.2 Trillion) for new more useable nuclear weapons and delivery systems (Obama and Congress already committed $1 Trillion to this illegal expansion while publically advocating for Nuclear Abolition) this sets the course for Nuclear Warfare. Its true that the US never has declared a No First Use policy and that the 49 nuclear missiles in NE Colorado are on launch on warning status still. The Bulletin of Atomic Scientists has set the nuclear clock to a 2 minute mark– the shortest since the 1950’s.
https://media.defense.gov/2018/Feb/02/2001872886/-1/-1/1/2018-NUCLEAR-POSTURE-REVIEW-FINAL-REPORT.PDF