Expansion of U.S. & Foreign Policy (College Board AP® US History): Study Guide

Timeline & Summary

Following the War of 1812, U.S. foreign policy shifted to focus on the Western Hemisphere with an emphasis on territorial expansion and asserting influence in the Americas. The United States worked to resolve border disputes, particularly with Mexico, which had not yet clearly defined the boundary with the land acquired through the Louisiana Purchase. 

The United States also began actively seeking to reduce Europe’s influence on the other nations of the Western Hemisphere, exemplified by the Monroe Doctrine, which asserted that the US would oppose further European colonization in the Americas. These policies set the stage for territorial growth and the US’s evolving role on the world stage.  

The Treaties of Ghent & Oregon

The Treaty of Ghent

• The Treaty of Ghent had ended the War of 1812, but the treaty did not resolve all issues, for example, border disputes

  • The Border with British North America:

    • The slogan “54-40 or Fight!”, (line of latitude) reflected demands from Americans who wanted the United States to go to war with Great Britain to expand the northern border further into British territory

    • Neither the United States nor Great Britain wanted to go to war

The Oregon Treaty

• The Oregon Treaty was signed in June 1846

  • The treaty set the U.S. border with British North America (Canada) at the 49^th parallel, extending to the Pacific Ocean

  • Vancouver Island stayed within British North America

  • British subjects who lived in the Oregon Territory south of the 49^th parallel retained the right to:

    • navigate the Columbia River

    • keep their existing lands 

Florida and the Adam-Onis Treaty

Florida

• Members of the Seminole, along with Black Seminoles raided settlements along the Georgia-Florida border as colonists started to move into Seminole territory

• In November 1817, the First Seminole War began when U.S. soldiers attacked a Seminole village killing 20 people

• The Seminole then captured a boat and killed over 40 men, women and children

• In December 1817, General Andrew Jackson became the commander of U.S. forces 

  • His troops attacked villages and pushed the Seminole into southern Florida

  • Jackson’s forces also seized a Spanish military post and the town of Pensacola

• These gains influenced Spain’s decision to give up its territory in Florida

Adams-Onis Treaty (1819)

• The Adams-Onis Treaty (1819) is also known as the Transcontinental Treaty

• Named after the signers:

  • John Quincy Adams (United States)

  • Don Luis de Onís (Spain)

• The key aim of the treaty was to:

  • formally defined the Louisiana Purchase’s western border

• Spain: 

  • ceded Florida to the United States 

  • gave up its land claims in the Pacific Northwest, including the Oregon Territory

  • retained control of Texas

• In Florida (after the treaty)

  • Some Seminole leaders signed a treaty with the United States and moved part of the tribe to what is now Oklahoma

  • Other Seminoles did not recognize the treaty and fled into the Florida Everglades to resist relocation

Monroe Doctrine

• During the early 1900s, the United States gained strength and political power on the world stage  

• It officially declared it had such power in its foreign policy on the Western Hemisphere

• By the 1820s, several nations in the Western Hemisphere had declared their independence: 

  • Mexico

  • Colombia

  • Chile

  • Peru

  • Argentina

• The United States established relationships with these new governments

Aims and reactions to the Monroe Doctrine 

• In 1823, President James Monroe declared the Monroe Doctrine policy in his annual message to Congress:

• The policy stated that:

  • the United States would not interfere in Europe’s wars or its internal affairs

  • the United States would not interfere with any existing colonies in the Western Hemisphere

  • no foreign nations would be allowed to establish any future colonies in the Western Hemisphere 

  • the United States would consider any European attempt to control a nation in the Western Hemisphere as a hostile act 

• The aims of the Monroe Doctrine were:

  • To discourage European nations from attempting to recolonize Latin America

  • To ensure commercial trade with countries in the Western Hemisphere, especially Mexico

  • To keep political power from returning to European nations

• The Monroe Doctrine was mostly ignored outside of the United States

• European nations had little interest in recolonizing Latin America

• The United States didn’t have the military or naval resources to enforce the policy