How is nationalism an important concept to the monroe doctrine?

  The Monroe Doctrine was a policy that was codeveloped by John Quincy Adams and put into effect by President James Monroe on December 2,1823.   The Doctrine stated that all nations (Europe in particular) were not able to colonize any further in the American Continents.  
       The new policy was put in effect because it eliminated the threat of foreign countries taking land that the United States wanted claim to.   The United States was fearful at the time that Spain and France would become allies to regain their lost empires.  The United States also wanted to keep Cuba in the hands of the Spanish.  Monroe and Adams believed that eventually Cuba would fall into the hands of the United States, a wish that never occurred.