Will China then play the role of the Soviet Union in the original movie, who supported the Cubans? So China would be the power behind the N. Koreans.
Nothing else would make sense.
I do have another scenario :)
The European Union goes through a severe financial crisis, one in which an economic collapse occurs. Nationalistic leaders like Anders Behring Breivik begin to emerge and restore financial order by seizing markets and putting the brakes on European financial markets. People see the likes of nationalistic leaders similar to Breivik as the saviors of Europe.
Russia joins forces with this new nationalistic EU and together plan an invasion of the US. This new alliance will then target China next.
China gets wind of EU/Russia plans to attack China. However, like the US before WW II, China is ill equipped to take on the new alliance. So, while the Alliance is preoccupied with defeating the US, China quickly builds her defense industry raising the defense spending from 2% of GDP to 50% of GDP.
The Alliance, after discovering China is intending to build up her military, begins a dual battle plan as they do not want to see China countering EU/Russian efforts. In the movie, all this would get conveyed to the teenagers in America through news reports, etc. But at first, they hear of severe defeats in China and wonder if they will have to take on the alliance alone.
While US forces and the "Wolverines" fight on, slowly news arrive of US forces repelling EU/Russia forces. But also, that a turn around had gone on in China which eventually lead to China cutting off EU/Russia reinforcements to the US. The "Wolverines" go on to defeat those remaining EU/Russian forces in North America.
I don't have the full script yet, but I'm working on it :)
There is one other twist I would add to the movie. The Wolverines encounter other American guerrilla groups. Except, they are fighting FOR the EU/Russia Alliance because the US and China are allies :) The Wolverines would question why these groups even exist but nonetheless are seen as treasonous enemies in the eyes of the Wolverines :)