Brotherhood War

The Brotherhood War is a major conflict between the Brotherhood of Steel and the New California Republic taking place in the former American Southwest and the Mojave Wasteland.

Background
As a result of the Brotherhood of Steel's disagreement with the NCR about how technology should be controlled, a series of violent confrontations took place. The length of the conflict has resulted in NCR commanders such as Colonel Cassandra Moore having completed four tours against the Brotherhood.

In 2274, the NCR moved into the Mojave Desert region to occupy Hoover Dam. A chapter of the Brotherhood was already active in the area and had been for several years, undertaking reclamation missions without opposition. This Brotherhood contingent and NCR forces engaged in minor confrontations for almost two years following the NCR's arrival. These conflicts included NCR platoons attacking six Brotherhood bunkers, four of which self-destructed.

As part of the ongoing conflict, the NCR attacked and occupied the Brotherhood's fortifications at the HELIOS One power plant, part of "Operation: Sunburst." The plant housed the Brotherhood chapter, where the faction was attempting to refurbish the facility and bring it back online. The Brotherhood leaders knew that the location was not defensible and that despite their superior equipment and training, the NCR outnumbered them by a wide margin. Due to these factors, when the NCR began to move in, senior paladins such as Hardin advised the chapter's leader Elder Elijah to fight a retreating action, but he refused. The elder ordered forces to defend the facility, insisting that he just needed "more time".

Despite the efforts to hold the plant, the Brotherhood forces were forced to retreat, suffered a loss of more than half of its paladins and knights, and the disappearance of Elder Elijah. The NCR consolidated their hold on the location and then set out to pursue any remaining Brotherhood forces, but found none, as the group had retreated to a nearby bunker.

After the loss at HELIOS One, the Mojave Brotherhood's new leader, Elder McNamara, restricted all activity outside of the bunker and forbade engagement with NCR forces. Afterward, the NCR left a small fighting force at the plant, sent the rest sent onward to Hoover Dam, and over the next few years, increased its military presence in the Mojave fivefold.

Appearances
The Brotherhood War is mentioned in Fallout: New Vegas.