The National Guard was a reserve component of the United States Army and served as a domestic defense and disaster relief force during peacetime. However, during wartime, they were also deployed abroad as front-line troops alongside other Army units.
Many National Guard units were dispatched to prepare for the likely event that China would attack American soil with nuclear weapons. Units from both the National Guard of the Commonwealth of Columbia and the National Guard of the Eastern Commonwealth were widely active in the Columbia Commonwealth and the Greater Washington area in the time prior to, during and following the Great War. In particular areas, like Washington D.C National Guard units were mobilized to provide security and assist in the evacuation of civilians from the Washington, D.C. and outlying areas in coordination with National Catastrophe Relief Auxiliary units.
The Capital Wasteland still has a widespread traces of the National Guard. National Guard checkpoints can be found dotted around the Capital Wasteland. These checkpoints are usually guarded by Army robots and contain radiation warning signs alerting people that they are near a highly irradiated area. A National Guard detachment from Pennsylvania was deployed to Germantown in the immediate aftermath of the Great War as mentioned in the terminal entries of Nancy Kroydon, Presiding officer of the National Catastrophe Relief Auxiliary - Response Unit MD-478, which was also deployed to Germantown on evacuation detail. With the nuclear holocaust on October 23rd, 2077 and the dissolution of the chain of command, the National Guard and the rest of the United States Armed Forces effectively ceased to exist, becoming groups of isolated soldiers with no coordination and many deserted or succumbed to the blasts and nuclear fallout of the war.