What is the purpose in declaring war? You can just walk on in to France and be like "Ok everyone, umm... yeah you guys get your asses kicked in just about every war so yeah. I'm the American President, and well you see... France is shaped like a star. So I think because of that reason, I'm going to turn it into one big jail. Everyone wears a leaf, and I have a few basic rules;
1. No cigarettes.
2. No snails.
3. Do NOT spit on the bars... they are made from the Eiffel Tower.
4. No wine. PERIOD.
5. We will be releasing wild herds of buffalo in the area, so do not be alarmed if they try to eat you leaf."
But if I was President for a day, the first thing I'd do would be getting a BIG crane, and picking up Israel, and placing them in Nevada to allow them to become our 51st state. Total Win.