Answer:
You can use the First Indochina War.
Explanation: The Vietnamese became victims of the French taking over their land and pushing non-communist ideas onto them. The Vietnamese were brought into the Cold War because of this and there were rising tensions because of Communist and anti-communist ideas.
Manifest Destiny is the belief that Americans were destined to expand across North America from coast to coast.
The Emancipation Proclamation is an executive order by Abraham Lincoln freeing the slaves.
The Monroe Doctrine was a United States policy of opposing European colonialism into the Americas.
Lastly, The Louisiana Purchase was the purchase of the Louisiana territory by the US from France.
Manifest Destiny is the best answer.
The Powhatan Confederacy was a group of Native American tribes during the 17th century that settled in Virginia. Learn about how they rose in power under Powhatan, how they reacted to English colonists at Jamestown, and how they ended up in decline.