I may have been a bit harsh in my last post here, sorry about that. So now i am actualy going to add something meaningful.
I am gonna hit on your story again and add on to it. But first i think you ment UN instead of NATO.
Your current story makes the USA out to be the "Bad guys" of the game. which could work out, but it also makes the rest of the world aligned againt the USA.
Heres my suggestion. Push the game further into the future, to about 2028-2032. At this point NATO has become like one giant country. The USA is now made up of canada and mexico and also extends partway down into south america. You still have the EU, might wanna make them encompass all of Europe. Have china and russia join up along with the other smaller asian countries, north korea, laos, cambodia, vietnam, burma. Have south korea, japan, autralia and the other small countries in that area form a neutral pacific coalition. have the Arabic countris form an Arab League, and ignore africa. Africa has nothing meaningful to add, besides being a battle ground. (not sure what to do with isreal)
Following your story, Roy BLommington becomes president and has is cold war crazy policies. He expans goverment while limiting some civil liberties and expands the USA further into south america. there is growing disent in america, mostly on the west cost and central america that extends into canada. While the southern states, east cost, mexico, and south america are firm supporters of the president.
Now taiwan does its stuff and china attacks. Roy attempts to declare war, but he can't get the senate and congress onboard, meanwhile the EU is against it. However the Arabic League, fearing china's expansion near its own territory is for the attack. Sensing his grand oppertunity to destroy china is disapearing, roy declares that the head senators opposing him are agents of china trying to keep the USA from helping taiwan, and has the imprisioned during a closed doors sesion of congress. With several Key opponets now jailed he has the majority and declares war. Without informing the public he orders the millitary forces he ordered into the area to launch a full attack againt china. He also calls on the Arabic Legue to attack china from the sides.
China is caught of guard by the suprise attack and while attempting to reorganize itself it gets attacked by the Arabic League, which invades into india and from afganistan into mainland china and russia through kazakistan, the arabic league also moves from turkey into greece, which proves a response from the EU.
Americas forces are quickly split into 4 tasks forces, each with several objectives. Task force alpha contains the greatest amount of naval assets out of the 3 taskforces. It only has 2 carriers but several battle ships, crusiers and destroyers. ITs primary objectie is to prevent the EU from sending any assitances to chian via the oceans, or to prevent an attack on America, its seconday objective is to drop off reinforcements for the Arab league forces in greece that are now facing the full weight of the EU's combined millitary. Task force alpha is commanded by admial (insert name here) who is very loyal to the president.
Task force Bravo is to go around africa and invade india and burma. the forces will conect the to areas and move northward to team up with the Arab league forces, and then push into china. task force bravo is the second smallest of the groups consisting of only 1 carriers, but containing all 7 of the navy's railgun equiped, Zumwalt class destroyers. Task force bravo carries more cround forces that Alpha but far less than task force Charlie. the ground forcers are commanded by Major general (Insert name here) of the marines and the naval forcers by Vice admiral (insert name), both of which have worked together in the past and are relativly moderate.
Task force charlie is comanded jointly by Admiral (name) and general (name), together they command the largest cluster of ammerican millitary strengh since WW2. The navel forces of Task force Charlie contains 7 out of the remaining 8 aircraft carriers and more ships than the other 3 tasks forces combined. Charlies also has more ground forces, both army and marines than the other forcers. Charlie was split into 3 sections, the first contained a single carrier and only a few support ships and ground forces, this is the group that was sent to tiawan and the group that launched the initail attack. this group consisted of about 10% of the total of Task for charlie and has sustained heavy losses. the second group was onder the comand of rear admiral (name) and was ordered to move through the south china sea and invade vietnam, eventualy moving north west and meating up with task force Bravo. the third group was the main body consisting of 70% of the entire taskforce and was going to retake tiawan and then invade china.
Task force delta is the homeguard. it contais 1 carriers and mostly older warships maned by the coastguard, its naval assets are stationed in pearl harbor hawaii. its ground assets are possitioned sparsly along the west coast and heavily along the east, however they are mostly national guardsmen and reservist, using less than top of the line equipment.
Now before the 3 attacking tasks forces get into position, the public learns of the war and suprise attack, and also the impisonment of the senators. The public and some of the military sees through the president's deception and declairs him a traitor and revolts. The wester and central united states, along with canada break away from what they are now calling the American Empire. Task force delta splits on geographic lines, the naval section teams up with the western united states, meanwhile the ground forces move to enact "martial law" on the west.
Task force charlie splits a detatchment of ground and sea forces to retake pearl harbor and then assult the west cost. the main body of Charlie continues on with its main task, however the 2nd group that was headed to vietnam instead pulls back and retreats to indonesia.
Task force alpha changes its mission goal and instead attacks ireland, the UK and iceland, which promtly fall and surrender. Alpha begins fortifing its positions and preparing for a larger attack againt against europe.
The EU is forced to divert forces from its battles against the Arab League to confront the larger treat of US forces.
However the EU gets some breathing room when Task forcer Brao goes rouge and instead moves into the Persian gulf and begins an attack against saudi arabia, iraq, and iran.
So a break down of forces.
Good guys, Weatern USA and canada (Most of Task force delta,Task force Bravo), China, EU
Bad guys, Eatern USA, or the American Empire east cost and southern states, mexico, and south america (eastern ground forces of task force Delta, Task force Alpha, and majority of task force Charlie), Arabic League.
Neutral, What remans of south america, africa, Pacific coalition, Task force charlie's second naval group.
And the Active battle fronts.
Eastern USA v.s EU at Britin, ireland, and iceland. (Task force Alpha)
Arabic league v.s EU at greece
Arabic League v.s EU +China at Ukraine (Pushed thorugh russia to hit there)
Arabic league v.s EU + China at Russia. (china and russia are one body at this point)(attacked from iran through georga.)
Arabic League v.s China at kazakstan (Kazakstan is part of china)
Arabic League v.s China at India.
Western USA v.s Arabic League at Saudi arabia, Iran, and Iraq. (Task force Bravo)
Eastern USA v.s China at china (entire coast of china) (Task force Charlie)
Eastern USA vs. Western USA at Pearl harbor. (Parts of TF Charlie v.s Navel assets of TF Delta)
Eastern USA v.s Western USA at midwest USA. (TF Delta v.s Loyal Elements of TF Delta)
Eastern USA v.s Western USA at North east USA (New York) (TF Delta v.s Loyal Elements of TF Delta)
Anyways thats my take one how this would best play out, and best work as a game. feel free to change or ignore all of it.