What was the role of America in WWI?

WWI occured as a result of political instability, alliances, arms build-up, mistrust, etc. Much simplified, here is what happened:

1. Archduke Ferdinand of Austria-Hungary was killed and Austria-Hungary believed that Serbia had something to do with it, so they wanted to crush Serbia.

2. Germany was an ally of Austria-Hungary, and promised to take their side and help them if they needed it.

3. Russia was an ally of Serbia, so they declared war on Austria-Hungary, so Germany declared war on Russia.

4. Germany knew France would not stay out of a war between Germany and Russia, so Germany declared war on France also.

5. Germany wanted to surround France, but to do so they had to go through Belgium. They asked permission and Belgium said no, so Germany declared war on Belgium too.

6. Great Britain was an ally of Belgium, so they declared war on Germany. And so began WWI. America was not involved at this point.

The war seemed like it would last forever. Neither side could force a decisive victory and neither seemed so superior that the other side was tempted to give up. When, at last, peace talks were held, the United States was involved and was a major player in events outside of itself for the first time in history.

President Wilson wanted the peace to be fair to Germany, while the Allies blamed Germany for what happened. Wilson gave a speech where he outlined the Fourteen Points that he thought would bring about a fair peace.