A giant robot built by the US government two centuries before the game's event which strides across the capital wasteland shooting lasers and throwing nuclear bombs like giant footballs shouting patriotic messages and decrying the Chinese communists as it goes. It concludes the game (which was the first Fallout Game many people played) in an over the top bombastic and frankly awesome way. So much so that he stomped back in Fallout-IV. Even so, I feel that a lot of franchise fans don't seem to understand the point of Liberty Prime, both in terms of the In-Universe and Out-Of-Universe perspectives in that they tend to quote his quotes and take them seriously despite how absurd this is.
The first layer of this is the most obvious: the Slogans that Liberty Prime shouts out are supposed to be pre-programmed lines said mostly at Random, all of which pertain to the Chinese Invasion of Alaska (2066-77). A Ship which had not only sailed but was nuked two centuries prior in general and made even more ridiculous by the fact that the group that it's marching against in Fallout 3 is The Enclave, born of a remnant the United States government and a continuation of the US twisted as it might be. Liberty Prime is pretty much those subway Protectrons that you activate to kill a few raiders beefed up. Another analog is the Computerized House in "There Will Come Soft Rains" which goes on even after a nuclear war wipes out everything around it unaware of the change beyond the immediate practical level. A short story which is directly referenced in the game itself.
But there is more to this than that, specifically reason why things had gotten so bad in the first place. Resources are listed as a motivation for the wars which culminated in nuclear exchange in the fallout universe and they were a factor in it, but things probably could have been sidestepped. Sure fossil fuels were being used up, but that issue was already being addressed by nuclear power. Fusion powered vehicles and power armor were already being mass produced more than a decade before the Great War. Codsworth waited for centuries after the war for the Sole Survivor to come back as have other robots. The Great War was not an inevitability. The United States could have given that technology to the Peoples' Republic of China and both powers could have tightened their belts for a bit and come into the twenty second century as being on the way to creating a Retropunk version of The Culture together. Instead the US fell into control of a set of corporate elites which covered up their power-plays with blustering nationalism who were more than willing to burn the world to get that power in the process. They went out of their way to refuse to do anything to address the PRC's energy crisis even when they had the capacity to do so (no export of oil, nor fusion technology) and left the government of the PRC with two choices, run on dry in a few years and collapse mad max style or invade Alaska. A situation made all the worse by the US Government sabotaging the Chinese efforts to drill for oil in the Pacific. The entire world of the franchise centuries onward is still dealing with the fallout of their callousness, greed and ambition.
This fits in with the themes of historic points that the series' setting alludes to: the Red Scare, Cold War escalation, McCarthyism and the general notion of the ideal Leave It To Beaver conception of the world being a facade covering up social and political issues that were festering. The series tagline "War Never Changes" is not a call to duty, it's a regretful commentary on a tragic element of humanity. If the US had the sort of Nationalistic jingoism that it had in Fallout in 1970 we would not be talking about the Fallout franchise. The people of that world that survived would be struggling to survive in one marred by nuclear war. Hundreds of millions dead from atomic weapons, hundreds of millions more dead from disease, starvation, malnutrition, radiation and so forth brought on by social and infrastructural collapse and subsequent fighting. This is a series which has nothing but contempt for nationalism and it's weird that people would use it for a source of nationalistic slogans.
Zor
