Chariots that were made out of iron.
The main reason why the Mayflower Compact was an important document for the Plymouth colony was because it spelled out basic rules that the settlers were expected to follow in order to maximize the likeliness of their survival. It was actually drafted and signed onboard the Mayflower before the settlers arrived.
Us influence began expanding in the 19th century, following Monroe Doctrine which defended Latin America countries from European influence in the same manner that is helped US shed off Britain. They later even engaged in help with troops and benefits, both in 19th, and 20th century, even now in the 21st.
Because they had nothing better to do