[quote=@ClocktowerEchos]
<Snipped quote by Dinh AaronMk>

Could just be corporations giving weapons to whom ever they want. Maybe special interest groups like far-left/far-right parties and organizaitons look at which factions they like the most and send some extra help their way.
[/quote]

It's really something that gets covered up in black up notions, but I don't think will ever really evolve into anyone straight up purchasing resources from one of these factions until they have formal control of the United States and haven't totally alienated the rest of the world. Since while certain groups could arm the factions they like, the global west may also embargo the United States to prevent or slow down the number of escalating weapons arriving inside the country.

One way to look at it too would be like when the British Empire embargo'd the colonies during the War for Independence to prevent as best they could French support ships coming in, and to capture congressional delegates heading out on diplomatic missions.

To add a layer of worry, the US is the second-most nuclear equipped country in the world. Politically instability here puts the nukes in the hands of groups with ambiguous goals. It would be in the interests of the outside world to make sure the conflict doesn't get any worse and to most importantly prevent the most radical groups from ever getting control of all the warheads.