@Dinh AaronMk
I just don't see how the US military vanishes the way the gm makes it sound like it does. All those assets are still out there and since you have players with control of states like texas or california access to US military assets should be more common than the GM makes it sound like.
I suspect it's a asymmetrical situation as I just don't see why some players wouldn't have access to jets, helicopters, ships and tanks. The situation isn't apocalyptic (no nuclear war between America and China occurred after all) and the US has tons of energy resources even if global trade has collapsed which it likely did as China is probably a pariah state over the destruction of the worlds orbital infrastructure and the global economy tanking is just inevitable in this situation.
True, but a large part of what was the American military was either in active deployment or already posted overseas. Roughly a third of the US armed forces serve overseas and the deterioration of the political climate at home would leave them at limbo or abandoned. It might be presumed it'll be difficult to recall them, or incapable of doing so. And with a large body of the US military also technically 'at float' in the Pacific a lack of satellite communication would cut them out too.
Further, civil conflict on this scale doesn't exactly invite economic activity. As is the case of countries going through civil war trade tends to avoid the country and to go around it directly. Systems of checkpoints at the edge of each faction's territory would create too much red tape and the chaotic situation would no doubt lead to corruption among any group, given that many factions may not be able to pay to keep pace with the devolving situation. Financial sectors like New York would be thrown into chaos with the region taken over by basically monarchist homeless people so any funds held by banks or private savings would have been wired over to Europe. So even if US military assets reached home its doubtful any group would be able to use all of it. Like with the battleships we have "saved" from WW2, carriers and large warships would be mothballed and set aside until someone can actually afford the upkeep and staffing requirements.