I have to do a political cartoon based on any event between the mid 1300's and 1812.

But I'm having a difficult time picking out what to do it on.
Does anyone have any ideas?

I suggest you choose your event between 1492 and 1812. Certainly you can think of a few events that happened in that 300-year period.

Google images may give you some ideas.

http://www.google.com/search?q=U.S.+history+cartoons&hl=en&prmd=ivnsu&source=lnms&tbm=isch&ei=XaTRTYC7NY-jtgfi4tCADg&sa=X&oi=mode_link&ct=mode&cd=2&ved=0CBUQ_AUoAQ&biw=853&bih=564