Update on my USA game:
I fought 2 Great Wars for 2 different nations.
The first came in 1912 when France offered me an alliance and invited me to fight against Germany who attempted to gain control of some border provinces. After shifting 120,000 troops to Europe, Germany was crushed and Berlin fell within a year of my troops landing on European soil.
Allies: France (leader), USA, Netherlands, Britain (her minor allies), Canada and Australia.
Central Alliance: Germany, Austria-Hungary, Belgium and Spain.
The second came in 1914 when the Netherlands called me in to defend against French aggression which then spiraled out of control as France and I called in our respective allies. This very bloody war ended in a status quo after I was forced to sack both Paris and London. This war took approximately 5 years and was fought mainly in the colonies, South America, Canada, Australia, Africa and India. Europe was a picture of Trench Warfare in which huge armies simply stood there and watched each other or when they fought it resulted in a long and bloody stalemate in which neither side can really claim victory.
Allies: USA (leader), Netherlands, US Allies (Mexico, Colombia, Venezuela, Panama, Honduras, Haiti, Brazil, Ecuador, Peru, Paraguay, Uruguay, Chile and Libera)
The other Alliance 
: France (leader), UK, Canada, Australia, Belgium, Savoy-Piedmont, Portugal, and of course the UK's minor allies in India and Asia.
I am now at 1919. I will post a map after my next game.
EDIT: I found it humorous how quickly loyalties in Europe change. Britain and Canada were both quick to discard their alliance with the most powerful nation on earth, which is the USA, while Belgium chose to ally with France after their brutal butt kicking in the last great war as France's armies paraded through Belgium. Germany chose to stay out of the next war and Germany's allies decided to stay with Germany. Though I would admit that had Germany joined on my side the war would have ended far more quickly.
But during all this Russia did the most ridiculous thing I saw in any game. They were originally allied with France and despite repeated attempts to bring them in the 1st war they refused. At the completion of the 1st war they discarded their alliance with France and went solo for several years until the next war started in which Russia approached us, the USA, for an alliance which I accepted, thinking I could bring the Russian bear against Europe. But again they refused to get involved. When that war ended they discarded our alliance and went solo again.
