Since the 1400's, European Nations have invaded and Colonized America. Spain was even named "bullies of the New World". Here, it shows Spanish soldiers discussing taking over more parts of America.
This...can't...be...happening
Monroe Doctrine
James Monroe is being told how European Nations want to further colonize the U.S. Specifically Spain wanting control over Latin America. Clearly, President Monroe isn't too happy about this and wants to do something about it.
Seriously?!
James Monroe presents the "Monroe Doctrine" to congress, a document explaining how the U.S will tolerate no more colonization, and "It is only when [their] rights are invaded...[they] resent injuries or make preparation for [their] defense"
Europe is outraged after the U.S announced the new document, but slightly fearful as well. They were upset that they were not going to be able to colonize more parts of America, but also scared of what might happen to them of they tried.
Europe realizes they have lost and they won't be able to cross the border to America if they intend to fight.
Finally, in 1823, the Monroe Doctrine proves successful and European Nations have stayed out of the U.S for good, making the U.S free from Europe's Colonization.