basically the Monroe doctrine declared that America was in opposition of European interference in the Americas.
Explanation:
the Monroe doctrine was definitely driven by American nationalism and this doctrine had big impacts on how the war ran its course, it probably actually would have caused the union(American government) to lose the war, but the south was looking for help from European countries and they tried making agreements that slave trade would continue in the Americas if the south defeated the north, this was big motivation for European countries to help and was a very dangerous thing to the north because they essentially would have had to fight on two fronts, so this caused the growth of the tension to rapidly increase. At least from what my text book tells me.
