Serbia wanted to become a independent nation
Germany wanted to expand the nations territory in Europe
Austria Hungary wanted to seek revenge against those who had assassinated Archduke Franz Ferdinand
France wanted to regain territory that the country lost in a previous war
Cause that their idols of course duhh
Personally, I would write on limited government. You could talk about the foundation America was built on, and how families should have the sole rights to decide what to do in their homes and country, without being so affected by the government!!