APUSH: Period 4, 1800-1848 - Manifest Destiny and Territorial Expansion, Texas, Oregon, Mexican-American War

Why This Matters

Manifest Destiny and Territorial Expansion were pivotal events in American history that shaped the country's identity, politics, and power dynamics. This period, spanning from the early 19th century to the mid-19th century, saw the United States expand its territory through the annexation of Texas, the Oregon Treaty, and the Mexican-American War. These events not only expanded U.S. territory but also led to the displacement and marginalization of Native American populations, the introduction of slavery into new territories, and the strengthening of the federal government's authority. Understanding Manifest Destiny and Territorial Expansion is crucial for grasping the complexities of American identity, the role of the federal government, and the ongoing legacies of colonialism and imperialism.

Key Events & People

• The Adams-Onís Treaty (1819): Established the border between the U.S. and Spanish Florida, setting the stage for future expansion.
• The Texas Revolution (1835-1836): Texans fought for independence from Mexico, eventually becoming the Republic of Texas and later a U.S. state.
• The Oregon Treaty (1846): The U.S. and Great Britain agreed to divide the Oregon Territory, solidifying U.S. claims to the region.
• The Mexican-American War (1846-1848): The U.S. invaded Mexico, leading to the signing of the Treaty of Guadalupe Hidalgo, which ceded large territories to the U.S.
• John Quincy Adams: Advocated for the annexation of Texas and played a key role in the Adams-Onís Treaty.
• Sam Houston: Led the Texans to victory in the Texas Revolution and later became the president of the Republic of Texas.
• James K. Polk: Supported the annexation of Texas and the expansion of U.S. territory through the Mexican-American War.
• Zachary Taylor: Led U.S. forces to victory in the Mexican-American War and later became president.
• Stephen F. Austin: Known as the "Father of Texas," he played a key role in the colonization of Texas and the Texas Revolution.
• Abraham Lincoln: Opposed the expansion of slavery into new territories and later became president, issuing the Emancipation Proclamation.

Cause & Effect Chain

• Cause: The Adams-Onís Treaty (1819) established the border between the U.S. and Spanish Florida.
• Effect: The treaty set the stage for future expansion, including the annexation of Texas and the Oregon Territory.

• Long-term consequence: The expansion of U.S. territory led to the displacement and marginalization of Native American populations.

• Cause: The Mexican-American War (1846-1848) resulted in the signing of the Treaty of Guadalupe Hidalgo.

• Effect: The treaty ceded large territories to the U.S., including present-day California, Nevada, Utah, Arizona, New Mexico, Texas, and parts of Colorado, Kansas, Oklahoma, and Wyoming.

• Long-term consequence: The expansion of U.S. territory led to the introduction of slavery into new territories and the strengthening of the federal government's authority.

• Cause: The Oregon Treaty (1846) divided the Oregon Territory between the U.S. and Great Britain.

• Effect: The treaty solidified U.S. claims to the region and led to the expansion of U.S. territory.
• Long-term consequence: The expansion of U.S. territory led to the displacement and marginalization of Native American populations in the region.

Essential Vocabulary

• *Manifest Destiny*: The 19th-century idea that the United States was destined to expand its territory across North America.
• *Territorial Expansion*: The process of the United States expanding its territory through the annexation of new lands.
• *The Adams-Onís Treaty*: A treaty between the U.S. and Spain that established the border between the U.S. and Spanish Florida.
• *The Oregon Treaty*: A treaty between the U.S. and Great Britain that divided the Oregon Territory.
• *The Mexican-American War*: A war between the U.S. and Mexico that resulted in the signing of the Treaty of Guadalupe Hidalgo.
• *The Treaty of Guadalupe Hidalgo*: A treaty between the U.S. and Mexico that ceded large territories to the U.S.
• *The Republic of Texas*: A short-lived independent republic that existed from 1836 to 1845 before becoming a U.S. state.
• *The Gadsden Purchase*: A treaty between the U.S. and Mexico that ceded land to the U.S. in present-day southern Arizona and southwestern New Mexico.
• *The Compromise of 1850*: A series of laws passed by Congress that attempted to balance the power between slave and free states.
• *The Kansas-Nebraska Act*: A law passed by Congress that allowed new states to decide whether to allow slavery, leading to pro-slavery and anti-slavery violence in the Kansas territory.

Common Student Mistakes

• What students often get wrong: The Adams-Onís Treaty was signed in 1821, not 1819.
• Correction: The Adams-Onís Treaty was signed on February 22, 1819.
• What students often get wrong: The Mexican-American War was fought over the issue of slavery.
• Correction: The Mexican-American War was fought over the issue of territory and the U.S. desire to expand its borders.
• What students often get wrong: The Oregon Treaty was signed in 1845.
• Correction: The Oregon Treaty was signed on June 15, 1846.

DBQ / LEQ Connections

• Possible essay prompt: Analyze the role of Manifest Destiny in shaping U.S. foreign policy during the 19th century. Be sure to include evidence from the Adams-Onís Treaty, the Oregon Treaty, and the Mexican-American War.
  • Specific pieces of evidence: The Adams-Onís Treaty, the Oregon Treaty, the Mexican-American War, the Treaty of Guadalupe Hidalgo, and the writings of John Quincy Adams and James K. Polk.
• Possible essay prompt: Evaluate the impact of the Mexican-American War on the U.S. and Mexico. Be sure to include evidence from the Treaty of Guadalupe Hidalgo and the writings of Abraham Lincoln and Stephen F. Austin.
  • Specific pieces of evidence: The Treaty of Guadalupe Hidalgo, the writings of Abraham Lincoln and Stephen F. Austin, and the events of the Mexican-American War.
• Possible essay prompt: Discuss the role of the federal government in shaping U.S. territorial expansion during the 19th century. Be sure to include evidence from the Adams-Onís Treaty, the Oregon Treaty, and the Mexican-American War.
  • Specific pieces of evidence: The Adams-Onís Treaty, the Oregon Treaty, the Mexican-American War, and the writings of John Quincy Adams and James K. Polk.

Quick Self?Check

1. What was the main reason for the Mexican-American War?
   • Correct answer: The U.S. desire to expand its territory.
   • Explanation: The Mexican-American War was fought over the issue of territory and the U.S. desire to expand its borders.
2. Who was the leader of the Texans during the Texas Revolution?
   • Correct answer: Sam Houston.
   • Explanation: Sam Houston was a key figure in the Texas Revolution and later became the president of the Republic of Texas.
3. What was the result of the Adams-Onís Treaty?
   • Correct answer: The treaty established the border between the U.S. and Spanish Florida.
   • Explanation: The Adams-Onís Treaty was signed in 1819 and established the border between the U.S. and Spanish Florida.

Last?Minute Cram Sheet

• The Adams-Onís Treaty was signed in 1819, not 1821.
• The Oregon Treaty was signed on June 15, 1846.
• The Mexican-American War was fought from 1846 to 1848.
• The Treaty of Guadalupe Hidalgo was signed on February 2, 1848.
• The Republic of Texas existed from 1836 to 1845.
• The Gadsden Purchase was a treaty between the U.S. and Mexico that ceded land to the U.S. in present-day southern Arizona and southwestern New Mexico.
• The Compromise of 1850 was a series of laws passed by Congress that attempted to balance the power between slave and free states.
• The Kansas-Nebraska Act was a law passed by Congress that allowed new states to decide whether to allow slavery.
• The Mexican-American War was not fought over the issue of slavery.
• The Adams-Onís Treaty was not signed in 1821.