Lesson Plan

The Korean War


This six-minute video provides students with an introduction to the Korean War, including its context within the Cold War, and the hardships faced by American soldiers on the battlefield. Focusing on President Truman’s decision not to seek a formal Declaration of War from Congress, the video also sets up a discussion about the evolution and expansion of presidential war powers.

This video was featured in an online class on The Cold War in partnership with The Gilder Lehrman Institute’s History School and Joe Welch, a 2018 Gilder Lehrman National History Teacher of the Year and Master Teacher.


Students will learn about:

  • How North Korean’s invasion of South Korea in 1950 played into U.S. fears that the Soviet Union and Communist China were intent upon spreading communism across the globe.
  • Why President Harry Truman responded to the invasion by framing America’s participation in the war as a United Nations “police action” rather than asking Congress to issue a formal declaration of war.
  • How Truman’s decision to avoid the Constitutional process for declaring war through Congress has affected American politics and foreign policy ever since.
  • Social Studies
  • World History
  • U.S. History
  • AP Human Geography
  • AP U.S. History
  • 1950s America
  • America as a World Power
  • Cold War
  • Communism
  • Harry Truman
  • The Postwar Era (1945-1980)
  • U.S. Foreign Policy
  • Congress
For Teachers

Essential Questions

  • Why didn’t President Truman seek a formal Declaration of War from Congress?
  • How did Truman legally justify sending troops to Korea without a formal Declaration of War?
  • How did China’s decision to send troops to Korea affect the outcome of the war?
  • Why did some members of Congress believe that Truman should have first consulted them and sought a declaration of war before sending troops into harm’s way in Korea?
  • How has Truman’s decision not to seek a formal Declaration of War from Congress affected the power of an American president to wage war and commit troops to battle?

Lesson Procedure

  • Although the Constitution provides Congress alone with the power to “declare war,” the last U.S. President to ask and receive a formal Declaration of War from Congress was Franklin Roosevelt in 1941, when he committed troops to World War II. After Harry Truman declined to seek a formal Declaration of War in 1950, Presidents have generally followed his example. In your opinion, is this a positive or negative legacy of the Cold War? Does it benefit America for our Presidents to have greater flexibility and authority in committing US troops to battle? Or should Presidents be forced to obtain a formal Declaration of War through Congress?
  • How does the Korean War demonstrate both the rising importance of the US as a global power, as well as the limits of that power?
  • From 1950-53, about a million and a half American men were drafted into the US armed services, and about 1.3 million volunteered for service. Thousands of men and women worked as nurses or doctors in mobile hospital units. If you had been old enough and healthy enough for combat or medical service in the Korean War, would you have volunteered to do so? Why, or why not?

Additional Resources

Check out the Gilder Lehrman Institute’s History School Origins of the Cold War classGilder Lehrman 
Transcript for "How the Korean War Changed the Way the U.S. Goes to Battle"Retro Report 

Analyze a complex set of ideas or sequences of events and explain how specific individuals, ideas, or events interact or develop over the course of a text.

Integrate and evaluate multiple sources of information presented in diverse formats and media (e.g., visually, quantitatively, as well as in words) in order to address a question or solve a problem.

Analyze multiple and complex causes and effect of events in the past.

Evaluate public policies in terms of intended and unintended outcomes, and related consequences.

Skill 3.A: Identify and describe a claim and/or argument in a non-text-based source.

Theme 6: America in the World (WOR).

Questions? Tips? Concerns? Reach out to our Director of Education, David Olson: dolson@retroreport.com