DEFCON

A typical DEFCON counter found at Sugar Grove or The Whitespring bunker.

Defense readiness condition (acronym DEFCON) was a system of alert ratings used by the pre-War United States Armed Forces to determine the readiness level of the American military, typically in response to deteriorating strategic conditions. It is mentioned multiple times in the Fallout series.

Ratings

The following ratings or readiness levels have been used by the branches of the pre-War American military. After centuries without maintenance, at least some DEFCON archives remain unavailable due to data corruption.

Rating	Color code	Description	Occurences
5	Blue	Lowest state of readiness	Likely observed in peacetime.
4	Green	Increased intelligence watch and strengthened security measures.	Likely the standard rating during the Sino-American War.
3	Orange	Increase in force readiness above that required for normal readiness	Reached on January 28, 2077, 16:32R, after the liberation of Anchorage.
2	Red	Next step to nuclear war	Reached on October 23, 2077, 09:13R, after IONDS reported possible nuclear launches from China.
1	White	Highest level of readiness, catastrophic destruction imminent or in progress. All nuclear safeguards disengaged, launches permitted.	Reached on October 23, 2077, 09:17R. Air Force nuclear bombers were deployed and response scenario MX-CN91 authorized. Nuclear exchange followed shortly after, becoming known as the Great War. Reached and maintained in Appalachia since the late 2080s after release of the scorchbeasts by Thomas Eckhart and the Scorched Plague epidemic.

Appalachian Automated Launch System

While regular nuclear forces stationed at strategic locations such as Fort Constantine near Washington, D.C. or the Hopeville Missile Base in California would be provided with launch codes once DEFCON 1 was reached, allowing them to launch missiles manually (some launch codes were simply eight zeroes, in fact, allowing instant launch with the USAF One-Touch Command SysOps) multiple bunkers established around Appalachia in West Virginia were monitored by a sophisticated autonomous system, the Appalachian Automated Launch System that would determine the DEFCON level on its own, determining whether the situation was bad enough to raise the rating and eventually permit missiles to be launched. The AALS was designed to prevent malicious or accidental launches by requiring DEFCON 1 to be reached before launch operations could commence. Other silo systems were also tied to the DEFCON rating, such as reactor restarts, to maximize readiness.

Once the system determined that the situation warranted elevating the alarm rating to DEFCON 1, it would enable the launches and activate autonomous systems of the Strategic Air Command to deploy automated convoys to deliver nuclear keycards, so that generals present in Appalachia could deliver the necessary final launch authorization.

While it was a sound system in theory, the system was entirely independent of military networks, and even if DEFCON 1 was reached previously, it could lower it depending on circumstances. After the Great War, it deemed that the situation in Appalachia was stable and reduced it accordingly, which obstructed plans by Secretary of Agriculture-turned-President Thomas Eckhart and his division of the Enclave to continue the nuclear war against China. While his underlings managed to figure out how to manipulate the automated promotion system to promote their staff to positions of power (e.g. promoting Ellen Santiago to general), they could not manipulate the DEFCON system in the same way and had to resort to methods of tricking it into observing a DEFCON 1-worthy situation.

Despite misgivings by Santiago and her men, Eckhart orchestrated increasingly disastrous outcomes upon Appalachia to simulate a "Chinese invasion," including releasing legions of Operation Trinitite Liberators and hordes of uncontrolled super mutants created in West Tek's Huntersville facility. Still, the system refused to raise DEFCON to stage 1, leading Eckhart to escalate further. When Santiago confronted the self-made President, he overpowered her and kept her in an artificial coma to retain access to her credentials. Without her interference, Eckhart played his final card and ordered the release of the scorchbeasts, inadvertently unleashing the virulent Scorched Plague upon the post-War inhabitants who were largely unprepared to stave off the epidemic. This act was the proverbial "straw breaking the camel's back" as a full-on rebellion broke out among the Appalachian Enclave, leading to a brief civil conflict between Eckhart's and Santiago's factions that ended with the Whitespring bunker's systems being sabotaged and causing the deaths of all humans within it.

Without any meaningful ways to mitigate the situation, DEFCON 1 remained in effect across Appalachia as the scorchbeasts and monsters created by the Plague they spread wiped out all human life in the region. By 2102, the only humans remaining were the inhabitants of Vault 76, safely sheltered within the bunker until the time of Reclamation Day. After the doors to Vault 76 opened and the Seventy-Sixers confronted the matter of Appalachia's chaotic state, events turned to them ultimately having to leverage the automated launch system in order to use nuclear weapons against the scorchbeasts, destroying their lairs and killing them in large numbers, allowing humans to return to the region in 2103. Even with the lessened presence of the Scorched Plague after the creation of an inoculation against its effects, the rating remained at maximum well after the turn of the 22nd century, with SAC convoys continuing to deliver keycards and missile silos manufacturing missiles endlessly, inadvertently leading to a state of all parties having indiscriminate access to nuclear weapons in the region.