The smallest country of the world, the Duchy of Grand Fenwick, declares war on the USA ... and wins!
Lesson: Do not mess with small countries!
"Dedicated to all the little nations who over the centuries have done what they could to attain and preserve their freedom. It is from one of them that I am sprung."
Leonard Wibberley (*1915-†1983)
The mouse that roared (1954), made into movie in 1959.