The doctrine cites eight reasons under which field commanders can ask for permission to use nuclear weapons: Below are some quotes from the executive summary of the document.
Note: After public exposure, the Pentagon has cancelled the doctrine, which did not change the overall U.S. policy which includes options for nuclear preemption.
[2] The White House and Pentagon guidance stated:[3] "The use of nuclear weapons represents a significant escalation from conventional warfare and may be provoked by some action, event, or threat.
... "Although the United States may not know with confidence what threats a state, combinations of states, or nonstate actors pose to U.S. interests, it is possible to anticipate the capabilities an adversary might use… These capabilities require maintaining a diverse mix of conventional forces capable of high-intensity, sustained, and coordinated actions across the range of military operations; employed in concert with survivable and secure nuclear forces" ... "The immediate and prolonged effects of nuclear weapons including blast (overpressure, dynamic pressure, ground shock, and cratering), thermal radiation (fire and other material effects), and nuclear radiation (initial, residual, fallout, blackout, and electromagnetic pulse), impose physical and psychological challenges for combat forces and noncombatant populations alike.
These effects also pose significant survivability requirements on military equipment, supporting civilian infrastructure resources, and host-nation/coalition assets.