NFU creates a safe harbor for the US and prevents reckless miscalculation.

There are many reasons why retaining the option of using nuclear weapons first is dangerous for the United States. If the president decided to cross the threshold and use nuclear weapons first against a nuclear-armed adversary (Russia, China, or North Korea), those countries would almost certainly retaliate with nuclear weapons, either directly against the US or against its allies. Maintaining a first-use option therefore increases the chance of a catastrophic attack against the US public.

In addition, if a nuclear-armed adversary is concerned that the United States might use nuclear weapons first in a crisis, that could increase the adversary's incentive to go nuclear first because of "use-it-or-lose-it" thinking—that is, the fear that if the US attacked first it might wipe out the adversary's nuclear arsenal. This kind of thinking creates pressure to use these weapons before they are lost.

Taking nuclear use off the table except as a retaliatory measure could reduce this pressure, which would help to slow the timeline in a crisis, allowing decision-makers more time to explore other solutions rather than quickly escalating the conflict.

An NFU policy would also reduce concerns about the US president's sole authority to order a nuclear attack, since these concerns have focused primarily on a possible order to initiate the use of nuclear weapons in a crisis. An NFU policy would remove the option for the president to order the use of nuclear weapons except in retaliation for a nuclear attack.