On September 3, 1939, in response to Hitler's invasion of Poland, Britain, and France, both allies of the overrun nation declare war on Germany.
answer: invasion of poland
If I am correct I think the answer is "Federalist Papers"
Answer:
Printing press
Explanation:
The printing press was allowed for quicker production of text, as well as having the ability to duplicate in the thousands. A single pamphlet would be carried from one town to another, where it could duplicate even more.