Land of Confusion:
Genesis
When the bombs dropped on that fateful day it was commonly believed that the United States had died in the fires of Armageddon, the American Eagle having died burning away in atomic fire. Yet still a few scattered enclaves of the old Arsenal of Democracy still remain scattered across the wastes of America and beyond. Descended from elements of the old American government who managed to escape to underground bunkers or pre selected safe zones when the bombs dropped. The mightiest of these remnants being the United States Emergency Restoration Government, centered around the Hawaiian Islands of the Pacific Islands.
Descended from surviving elements of the American Military from the Pacific Island and Mainland Asia campaign, alongside a few scattered elements of the US civilian government. The few scattered remnants having fought their way to the Hawaiian Islands against surviving elements of the Communist Block in the region. With the likes of General Murdoch's forces gaining particular notoriety, having already possessed a reputation for unrestrained savagery and brutality even before the bombs dropped he ordered is troops in Southern China to kill & destroy everything in their path that weren't fellow Americans, as they fled to the coast. The scattered bands of the once mighty American Military coalesced towards the Islands after recieving an encoded transmission "To any Citizen of the United States of America this is President John Keller, formerly Secretary of Interior, if you are listening to this then the worst has come to past. Effective immediately I have declared an emergency government for the foreseeable future, any surviving elements of the US military are to rendezvous at the Hawaiian Islands... may god help us all."
The following years would be a time of hardship, rage and grief for the citizens of the Emergency government. As food shortages soon arose on the island's while the storm clouds of nuclear winter emerged upon the horizon. Seeing no other option the military went on a rampage across the Pacific attacking and pillaging anything within range of the surviving fleet, the surviving soldiers and sailors taking out their pain on surviving town or village they found. In a desperate attempt to gather enough suppliers to survive the coming winter, as they took refuge in the various island tunnel and bunker complexes that were built across the Pacific Islands during the second and third world war.
Against all odds they managed to survive though not winning sacrifices. As the American people struggled to carry on in the years to come with President Keller having been forced to resort to draconian methods in order on preserve what he believed to be last embers of the light of liberty... something he would deeply regret in his final years. With the exception of the Murdoch Expedition having sent the "Beast of America" and his most dangerous colleagues and followers back to mainland East Asia under orders to hunt down and eliminate what any potential surviving communist military elements. Murdoch and the last of his loyalists having died ten years later in Indochina at the hands of Asian warlords after being left to die as soon as they arrived on the continent.
Since then the U.S Emergency Restoration Government and their Pacific holdings has been in a state of isolation. With the wider world having been declared too heavily contaminated by radiation to reclaim until recently. As various political parties within the government begin to debate on which course to take with there currently being three major parties with their own respective stances on the subject. With the Democratic-Republicans believing that the best course of action for the foreseeable future is to maintain the ongoing policy of isolation. While the revivalists having long believed that the reason America suffered so much in the Third World War and its aftermath was because the old Republic had grown weak & complacent in the decades leading up to war, believing that not only must reclaim the old American homeland but also expand it beyond a old borders and cleanse it of the mutated subhuman savages that have desecrated their rightful lands. With the Structuralists on the other hand believing that they should help rebuild the wasteland, with the restored governments beyond the borders of America acting as client states and that any of the new states that have arisen within the confines of old American could gradually be integrated peacefully of their own accord, along with believing most wastelanders could be "civilized" within time.
("New white house and Capitol building")
Only time will tell what path the Remnant will take but until then their armed forces stand ready to defend America. With most soldiers still using the same combat armor and assault rifles that their several times great grandaddy's used in WW3, the USERG's island holding lacking much in the way of raw material and industrial capacity for the large scale R&D of their predecessors. Instead preferring on reliable and proven technologies in both the civilian and military fields for the day to day. Though that isn't to say that they've been completely stagnant since the bombs dropped in 2012 with their powered armor being far superior to their WW3 counterparts, having been gradually improved over the generations.
While their marines and heavy infantry are often equipped with plasma weaponry, once only being equipped to the most elite units during WW3 for field testing is now the go too standard issue weapon for such units. Finding it preferable to particle beam weaponry in jungle combat and the bloody mess they make having rather useful psychological effect against enemy combatants. Though that doesn't mean that they're above augmenting their forces with modified WW2 equipment and weaponry. Find such equipment to ne generally easier for their troops to maintain and repair on deployment with their limited industrial base, compared to pre Armageddon America.