The answer is ''To exercise diplomacy or force''
Between 1812 and the American Civil war, the Untied States was gradually becoming a major regional player.
It was both growing in Territory as well as the economy.
It was also looking to develop a powerful Navy and gave officers to right to carry out diplomacy with the nations they encounter or use force if necessary.
B. Horses and C. Diseases but mostly C
Well, I’m sure that’s not true… did anything happen to make you feel that way?
