Question

How did some Americans justify their taking over Spanish and Seminole land in Florida?

Answer 1

Spain was fighting a losing battle against revolutions in South America. Florida was mostly a vast swampland, and, being separated from the rest of the Spanish territory, it just caused a dispersal of military manpower. Added to the U.S. however, it would make borders tidier and more defensible, largely preventing, for example, the sort of north-south pincer movement the British tried in 1814.

Answer 2

After the French and Indian war, the Treaty of Paris was signed, saying the British colonists won ownership to Canada, the Great Lakes, Ohio River valley, and Florida