Nuclear War Expansion Cards
Created by Bernard HP Gilroy and students
(c) 2005 Gilroy. Free for non-profit use.
More information (including a consolidated list) is available.
Special
DEFCON 1

Card
Text

The heightened state of readiness of your rocket forces allows a rapid response to provocation.

Play immediately after an enemy has detonated a nuclear warhead on your nation. You may immediately play against that nation a missile/warhead combination from your hand.

It does not become your turn.
Additional Notes and Information:

DEFCON is shorthand for "Defense Condition", a numeric value indicating the readiness of US strategic forces. Like many children of the 80s, I learned about this through the amazing movie WarGames, and I'll let that movie's classic dialog explain the card:

McKittrick See that sign up here - up here. "Defcon." That indicates our current defense condition. It should read "Defcon 5," which means peace. It's still on 4 because of that little stunt you pulled. Actually, if we hadn't caught it in time, it might have gone to Defcon 1. You know what that means, David?
David No. What does that mean?
McKittrick World War Three.

The US has never reached DEFCON 1 (obviously) and has apparently only been at DEFCON 2 once (and that was only SAC, not the whole military).

The icon is of course numbers counting from "safe" green up through "war" red, in mimicry of the Homeland Security alert system. It also looks like a countdown to oblivion, which was also intended.

-=-BhpG 2005:0710