The Monroe Doctrine is the most significant event in American history in the 19th century.

Most people do not know what the Monroe Doctrine is. When it comes to American History, events such as the Declaration of Independence, the introduction of Tennessee to the Union, or the Louisiana Purchase are declared to be the most significant events in the history of the United States. However, the Monroe Doctrine is unquestionably the most significant single event in the history of the United States; it made the United States what it is today. The Monroe Doctrine was a statement presented to Congress by President James Monroe on December 2, 1783, that dictated separate spheres of influence for the Americas and Europe, as well as non-intervention and non-colonization in the Americas.

The Louisiana Purchase, the acquisition of more than 828,000 square miles in North America from France, more than doubled the size of the United States. This gave the United States the space to expand, and gave the United States virtually unlimited resources, at the time.

[Unidentified young soldier in Union uniform and f...

English: Newspaper cartoon from 1912 about the Mon...

James Monroe, fifth President of the United States

Napoleon Bonaparte said that it would "affirm forever the power of the United States." It was a moment where an American president did what many called unconstitutional for the sake of the nation, and as such is quite significant. The Monroe Doctrine is similar in that an American president stood up in the face of critics and made a political leap. The first political move of its kind, Monroe effectively told Europe to stay out of North America. However, the Monroe Doctrine is understandably more important than the Purchase, as it affirmed the America's control of the entire Americas, as opposed to an admittedly large section of North America.

While Tennessee is undoubtedly the most important state in the Union, the Monroe Doctrine is more important than the introduction of Tennessee to the Union for several reasons. While Tennessee is...