US FOREIGN POLICY: from expansionism to retrenchment

1803-Louisiana Purchase

Jefferson doubles US territory, launching westward expansion

1823-Monroe Doctrine

5th US president James Monroe warns European powers not to interfere in the Americans

1846-1848: Mexican-American War

US victory adds vast territories (California, Texas) Manifest Destiny becomes reality.

1898- Spanish American War

Defeat of Spain marks the US’s arrival as a global power (gains: Puerto Rico, Guam, Philippines)

1919-US rejects the League of Nations

After WW I, Congress refuses to ratify the treaty of Versailles, making a turn inward, despite it being based on President Woodrow Wilson’s 14 points promoting self-determination of nationhood.

1933-Roosevelt’s “Good Neighbor Policy”

The US renounces armed intervention in Latin America promoting diplomacy instead

1941-Pearl Harbor

The attack ends US isolationism. America enters WW II and becomes the “arsenal of democracy”

1947-Truman Doctrine

Launch of the Cold War: the US vows containment against communism and support “free people”

1955-75-Vietnam War

Massive US intervention in Southeast Asia-ends in defeat and dillusionment

1991-end of the Cold War

The fall of the iron Curtain leaves the US as the world’s sole superpower and promoter of liberalism

2001-9/11 and the War on Terror

The US intervenes in Afghanistan and Iraq to fight terrorism and spread democracy

2011-Withdrawal from Iraq

Obama ends combat operations; instability and the rise of the ISIS follow.

2021- Withdrawal from Afghanistan

After 20 years, the US ends its longest war-symbolizing the limits of “nation-building.” Nonetheless, this creates a vacuum allowing the Taliban to return to power.

2017-21-Trump and America First

Retreat from global institutions (UN, WHO, UNESCO), trade wars, and skeptic towards NATO

2022-2025-The Ukraine War

The US leads Western support for Kyiv but faces war fatigue and growing debate over the burden of global leadership