Greek city states military strength?

The Athenian military was the military force of Athens, one of the major city-states (poleis) of Ancient Greece. It was largely similar to other armies of the region – see Ancient Greek warfare.

Sparta was a warrior society in ancient Greece that reached the height of its power after defeating rival city-state Athens in the Peloponnesian War (431-404 B.C.). Spartan culture was centered on loyalty to the state and military service

Explanation:

a. because the u.s. was the leading with the most technology, economy, etc. also was teamed with other allies witch boosted the economy and materials to improve technology and use it.

disease was the number one killer of native peoples. they had had little exposure to the diseases of europe. this led to some villages being almost completely wiped out and some tribes destroyed.