Question

what did Monroe doctrine state

Answer 1

The Monroe Doctrine was a U.S. foreign policy regarding European countries in 1823. It stated that further efforts by European nations to colonize land or interfere with states in North or South America would be viewed as acts of aggression, requiring U.S. intervention.

This site explains it in detail:
http://www.ourdocuments.gov/doc.php?flash=true&doc=23

Basically, it warned European powers not to interfere in the affairs of the Western Hemisphere.

Hope that helps!