They emigrated for political reasons.
Answer:
They did not believe the Federal Government had the right to interfere with their commerce.
Explanation:
Living in a southern state, one of the few things we focused on in history was this :D
Basically: everywhere - and not only in the western hemisphere, they claimed all lands that were not claimed by another country that they respected the authority of.
There was actually this very interesting treaty, where Spain and Portugal divided the world (Treaty of Tordesillas), where they divided the world (expect for Europe) among themselves. That left Americas almost completely in the hands of the Spanish, and Africa in the hands of the Portuguese.
The War Powers Resolution requires the President to inform Congress within 48 hours that he or she has entered a military engagement by committing troops overseas. It also stipulates that these troops cannot be engaged in this conflict for more than sixty days without authorization from Congress.