| ||For the US West Coast conflict in which the Brotherhood of Steel support the NCR against the Enclave, see NCR-Enclave War.|
We stand now, at the precipice. Our great nation once more threatens to crumble, to topple into the sea of lawlessness and despair that has ruled us all for over two hundred years. In short, my dearest America - we are at war. Even as I speak these words, fearless Enclave soldiers are fortifying their positions at the great water purifier, bracing for an inevitable assault. The Brotherhood of Steel, in their arrogance, has claimed Project Purity as their own! They would steal the Enclave's work, steal America's water! It is only a matter of time before the traitors march on the purifier, and attempt to take it by force. Let them come! Wave upon traitorous wave will crash against the Enclave's walls! The Brotherhood of Steel will fail! All those who oppose the Enclave will fail! I am President John Henry Eden, and this is my pledge -- no one, NO ONE will take this great nation away from me! God bless the Enclave! God bless America!”— John Henry Eden
When the Brotherhood arrived in the Columbia Commonwealth area in 2255, they did not yet know that the Enclave, who were defeated by the California chapter of the Brotherhood and the New California Republic sixteen years ago, had fled to the Columbia Commonwealth, establishing a headquarters at the pre-war U.S military base Raven Rock. Under the leadership of Owyn Lyons the Brotherhood began combating the local super mutants, unaware of the rebuilding Enclave.
In 2257, the Enclave commenced a propaganda campaign against the Brotherhood. The Enclave, now under the leadership of president John Henry Eden, plotted in secret at Raven Rock. For twenty years, there was no interaction between the two factions, leading many to suspect the Enclave radio broadcasts were on an old loop. However, in 2277, Colonel Augustus Autumn led an attack on the Jefferson Memorial, and took over Project Purity, as part of their plan to "purify" the wasteland. James was among those killed, and the Lone Wanderer and the other survivors escaped to the Citadel.
The Brotherhood Outcasts were also attacked by the Enclave on patrols. Occasionally, the Outcasts would also launch attacks against the Enclave, but they were fairly unorganized. Protector Henry Casdin largely left the Outcasts out of the war.
After the capture of the Jefferson Memorial, the Enclave began their conquest of the Columbia Commonwealth, establishing many small camps and outposts throughout the Capital Wasteland. They even tried to annex Vault 101, but were denied entry by its isolationist overseer.
The Brotherhood set out to collect evidence that Project Purity could function in order for them to reclaim the Memorial. The Enclave caught on, and kidnapped the Lone Wanderer in Vault 87, confiscating the G.E.C.K.. The Lone Wanderer awoke in captivity inside Raven Rock, and was interrogated by Colonel Autumn. President Eden then distracted Autumn and sent him elsewhere, and then summoned the Lone Wanderer to his office, where he was revealed to be a ZAX computer. The former recruited the latter to act on his behalf, gave them a vial of Modified FEV to insert into the purifier to cleanse the wasteland, and then facilitated their departure from Raven Rock.
After the Brotherhood received word that the Enclave possessed the means to activate the purifier, they launched an operation to reclaim the Memorial with the support of Liberty Prime. The Brotherhood forces and the Lone Wanderer stormed the memorial and confronted Colonel Autumn, then started the purifier. Two weeks later, the Brotherhood started delivering the water throughout the wasteland. The Enclave, after its defeat, made a last stand at Adams Air Force Base. When the Brotherhood invaded the Enclave's satellite relay station, the base was destroyed, but Liberty Prime was eliminated by orbital missile strikes, a major blow for the Brotherhood. The Lone Wanderer scoured the ruins of Old Olney to retrieve a Tesla coil to assist in the scribes' research in Tesla cannons - the Brotherhood's last chance of countering the Enclave's VB-02 Vertibirds. After creating the Tesla cannons, they launched a final attack on Adams AFB. The Enclave laid a final stand, but were utterly defeated by the Brotherhood.
The launch terminal for the Bradley-Hercules orbital strikes indicates that the Enclave had given themselves the means to eradicate the settlements of Megaton and Rivet City. They also had Project Purity and the Citadel as targets. The Lone Wanderer can target the Citadel if desired and destroy the Brotherhood's headquarters or target Adams and conquer the Enclave. Neither option has been confirmed as canon.
If the Brotherhood won, they would still continue to have problems with the Enclave as despite the destruction of Adams Air Force Base, remnants of the Enclave will continue to roam the wasteland, but will not pose as great of threat as before and have no known goal. If the Citadel was targeted, the Brotherhood would be destroyed and with its leader dead and most likely the Lyons Pride being dead, they would have no clear goal and an uncertain future.
- Capture of Project Purity
- Destruction of Raven Rock
- Battle of Project Purity
- Battle of Rockland
- Battle of Adams Air Force Base