Thank you for this post.
If you take the principles of Republic and democracy backwards to the Ancient Greeks (400 BC) you can see that just after the Persian Wars, Athens behaved like the US in many ways -- it was enthusiastic about its democracy and tried to "export" it to it's neighbors and neighboring states (city states).
Yet it went against a heavily militarized state (Sparta) and in the Peloponnese Wars it lost and was devastated by the Spartans. Athens never rose again and was a few decades later taken by the war-like Macedonians..