How did the Monroe doctrine assert american nationalism?

The Monroe Doctrine declared that an y nation enacted any unwanted advances among the New World as an act of aggression toward the united states. The Monroe Doctrine conjointly believed that each country has a right to defend itself from any outside invasion. He also promised to protect America from the invasion of British or any other country to be its colony. This was an awfully generous supply to all or any collection countries among the Americas.

The Monroe doctrine asserted American nationalism by proclaiming that any further attempts by European powers to colonize or interfere in the business of places in the Americas would be seen as an act of aggression by the US.