The philosophy drove 19th-century U.S. territorial expansion and was used to justify the forced removal of Native Americans and other groups from their homes. The rapid expansion of the United States intensified the issue of slavery as new states were added to the Union, leading to the outbreak of the Civil War.
Bear flag Revolt
Explanation:
Known as the Bear Flag Revolt, a reference to the short-lived republic’s flag, this event was something between an American invasion and a miniature war of independence. Though the fighting was limited and the country it established lasted less than a month, the Bear Flag Revolt led directly to the American acquisition of what is now its most populous state.
They were getting worse and worse through the 1930's.
To conquer more territory
