What is the overall message in this political cartoon?

The motive of the cartoon here is the drive of the US territorial expansion. It attempts to depict a supposed never-ending hunger for more and more land in the 19th century.

Explanation:

i belive the classic sword and a shield would do

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.