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Manifest Destiny and the U.S.-Mexican War: Then and Now

Click here to print this lesson plan or download the PDF version [259k].

Grade Level(s):

6 - 12

Subject Area(s)

Language Arts - Reading and Writing, Civics, Geography, U.S. History

Estimated Time

One to two 45-50 minute class periods


At the time of the U.S.-Mexican War (and the height of the popularity of Manifest Destiny), there were some Americans who spoke out against what they regarded as a war of aggression. However, for the most part, the American public supported the war and the idea of Manifest Destiny itself. Today many historians see things differently. Historian David Pletcher writes of the U.S.-Mexican War: "This war was an aggressive war in which we attacked a neighbor and however much we won from the war, we do not like to look at the way in which we won it." Pletcher's idea may be borne out by the following two facts: there is still not a federally-funded memorial to those who fought in the U.S.-Mexican War and this war is so little studied and known about in the United States.

In this activity, students will explore different American opinions about the U.S.-Mexican War (and by extension, Manifest Destiny) from both the 19th century and today. Students will then apply their knowledge by having a debate on the topic.


Students will:
  • Consider the elements of Manifest Destiny that were attractive and exciting to Americans.
  • Learn about some of the voices that at the time opposed the U.S.-Mexican War and the idea of Manifest Destiny.
  • Research American historical perspectives (then and now) on the war and Manifest Destiny.
  • Work in a team to prepare their research to be used in a debate.
  • Participate in a debate with their classmates, with one side representing the consensus mid-19th century view on Manifest Destiny and the other representing modern-day perspectives.

Materials Needed

This activity can be completed using a computer lab where students can access the video clips and handouts themselves via The U.S.-Mexican War website. It can also be conducted by using one classroom computer with a projection device. In the second scenario, you will need to provide the students with the following handouts:

Video clips used:


Pre-viewing Activity: Briefly review the previous activity. Then ask students to read the brief article An Ideal or a Justification from the U.S.-Mexican War site. Discuss the complexity of Manifest Destiny with the students. Reference the dichotomy cited in the article, in which Pletcher discusses how Manifest Destiny was both racist and idealist.

Briefly review the two quotations on the Then and Now worksheet and go over the following questions with students before they watch the video clips:

  • What do you think was the general view of both the war and the idea of Manifest Destiny in the mid-19th century United States?
  • What do you think Americans liked about the idea of Manifest Destiny then?
  • While opponents to the war and Manifest Destiny were in the minority at the time, what were some of their arguments?
  • What is your sense of modern-day perspectives on Manifest Destiny?
  • Why do you think that the U.S.-Mexican War is so little studied today?

Explain to the students that after they have done their research, they will be engaging in a debate about the idea of Manifest Destiny, with one side representing the consensus mid-19th century view and the other representing modern-day perspectives of the historians they have read. Break the students into the two groups now or after the viewing activity.

Viewing Activity: Tell students to go to “The U.S.-Mexican War” website to access the video clips “The war and slavery: Some American voices of dissent,” “Looking back: A just war?” (or display the videos with a projection device in your classroom). Ask students to pay special attention to the content about people's attitudes toward the war and Manifest Destiny. Have the students use the Then and Now worksheet to focus their viewing as they watch the videos.

Post-viewing Activity: Have the two groups get ready for their debate. Ask each group to prepare a two-minute opening statement for their side of the debate. Also ask them to create a list of four points that they would like to address during the debate and to share that list with the other group. Once the groups have completed their preparations, have the students begin the debate by making their opening statements. Then have the groups go back and forth presenting each of their four main points, always allowing the opposition to respond to each point. Finally, have one person from each group summarize their side's position.

After the debate, ask the students to share their responses to the experience. Ask them to consider how attitudes toward Manifest Destiny and the U.S.-Mexican war have changed through time. Ask them to consider a popular modern-day ideal and question whether attitudes toward that ideal might also change over time. What might account for those changes? Is it easy or hard to imagine those changes?

Classroom Assessment

To assess the students' work, consider the following:

  • Did the students show that they had a good grasp of the historical perspectives on the war and Manifest Destiny?
  • Did the students make their arguments clearly and persuasively?
  • Did the students on each side work well together as a team?
  • Did the students show an understanding of the material in the questions that they asked the other side?

To further assess the students' work, you might use the questions on the worksheet (and any additional ones you would like to add) as a graded assessment.

Extensions and Applications

Have students research more of the articles on the U.S.-Mexican War site to more deeply explore Mexican and Indian attitudes toward Manifest Destiny. These articles are a good starting point:

Have the students read the Declaration of Independence (especially the 2nd paragraph) and analyze whether Manifest Destiny was a realization of the American ideal or a betrayal of it. They can find the Declaration of Independence on this web site.

Another possibility is to have students use the interactive timeline on the U.S.-Mexican War site as a starting point for research on the history of slavery in the United States. Further research could also be done on this web site.

For younger students: Much of this activity can be taught to younger children as it is. However, you may consider having a classroom discussion rather than a debate around the different historical perspectives. Another possibility would be to have younger students look at the painting "Westward Angel," which can be found on this web site.

Ask the students to think about the components of the painting and what they represent in terms of Manifest Destiny. Can they imagine such a painting being created today? Why or why not? (A study of this painting could also be successfully incorporated into the main activity for older children.)

National Standards

McRel K-12 Standards Addressed:

Language Arts

  • Standard 4: Gathers and uses information for research purposes.
  • Standard 5: Uses the general skills and strategies of the reading process.
  • Standard 8: Uses listening and speaking strategies for different purposes.


  • Standard 14: Understands issues concerning the disparities between ideals and reality in American political and social life.
  • Standard 23: Understands the impact of significant political and nonpolitical developments on the United States and other nations.


  • Standard 6: Understands that culture and experience influence people's perceptions of places and regions.
  • Standard 9: Understands the nature, distribution and migration of human populations on Earth's surface.
  • Standard 12: Understands the patterns of human settlement and their causes.
  • Standard 13: Understands the forces of cooperation and conflict that shape the divisions of Earth's surface.

U.S. History

  • Standard 9: Understands the United States territorial expansion between 1801 and 1861, and how it affected relations with external powers and Native Americans.
  • Standard 10: Understands how the industrial revolution, increasing immigration, the rapid expansion of slavery, and the westward movement changed American lives and led to regional tensions.
  • Standard 11: Understands the extension, restriction and reorganization of political democracy after 1800.

Online Resources

Below are the links for sites referenced in this activity:

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