It is also the perfect unit to gift to a city state when you want them to have more fight in them (Two of these with a cannon is a mighty gift indeed!). The Minuteman is an excellent hybrid unit useful for mantaining control of a hot border region. He is best used with an expansionist with a limited war doctrine. I very often put a city or two close to opposing cities and steal all the tiles leaving him with a weak city not capable of developing well. You are always working the best tiles and you are taking land away from your enemies at the same time you are purchasing it for yourself. WAshington can scout and scoop up land and expand like no other. The most powerful part of the manifest destiny is the tile grabbing. I respectfully disagree with the posters assessment that you should play Gerorge WAshington as a warmonger.
