P5 | APUSH | Ms. Wiley | Mexican-American War, D___
Name:
Background: Most American historians call this war “The Mexican-American War,” while Mexicans continue to refer to it
as “The U.S. Invasion.” The difference in referral is based on the different perceptions of the conflict. This exercise will
help us to understand the roots of these distinctive perceptions and, ultimately, arrive at our own conclusions regarding
the nature of the conflict and how it should be remembered in the United States.
Questions for Consideration: To what extent was the Mexican War a “justifiable” war and not simply an excuse
perpetrated upon the American people in order to seize land from a weak neighbor? Was the United States justified in
taking half of Mexico's territory in the Treaty of Guadalupe Hidalgo? Was Manifest Destiny an aggressive imperialism
pursued at the expense of others? Or, were American actions justified by economic, political, and ideological impulses?
Instructions:
1. Read the outline on the Mexican-American War. Consider the questions above as you read and answer any
corresponding questions.
2. Review the attached documents. Mark them up and record comments throughout. You should have a significant
amount of commentary by each document. Consider the questions above as you analyze each document.
3. Prepare to share your thoughts on the questions above in a debate on the Mexican-American War. You will be
evaluated on your participation, which may come in the form of offering an opinion, posing a question (to the group
or to a particular student), etc. Feel free to do outside research if you would like, but be sure to use credible sources
and be prepared to share those sources if you are going to bring up those points in the class debate.
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Polk & Manifest Destiny
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Campaigned on expansionist principles
o Wanted Texas, NM, CA and lucrative trade across Pacific
o Saw expansion as a remedy to population growth, increasing immigration, and economic problems, as well as a creator
of democratic impulses
 Frontier areas offered inexpensive land and opportunity for self-advancement
Edged out Clay in Election of 1844
Polk interpreted victory as a mandate for expansion
Post-’45, Mexico-U.S. Relations
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Mexico had never recognized the Republic of Texas
Border dispute:
o U.S. took Texan view (since ’36)—boundary was at the Rio Grande
o Mexico took view that border should be what it was under Mexican rule—
Nueces River
Mexico feared that the U.S. would seize other Mexican provinces and potentially
attempt enslaving the Mexican people
Slidell Incident, 1845
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John Slidell was sent to Mexico to offer 30 million for Rio Grande boundary, NM
and CA territories
Mexico refused to receive Slidell and asked him to leave
Polk enraged—a challenge to “U.S. honor”
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Sent General Zachary Taylor to Rio Grande to protect Texans in event of Mexican aggression
From Mexican perspective, this was an invasion—sent their own troops to Rio Grande
Polk knew any attack on U.S. troops would garner support in Congress for declaration of war
Skirmishes; 11 U.S. soldiers killed  Polk had fuel for war  Congress [overwhelmingly] declared war shortly thereafter
1.
Evaluate the decisions made by Polk in 1845 regarding Texas and Mexico:
Opposition to “Mr. Polk’s War”
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Though many Whigs/Northerners opposed the war, most supported the declaration of war due to lessons learned from the War
of 1812
Viewed the war as a Southern conspiracy to extend slavery into Mexico and South America (unlimited slave states)
Questioned Polk’s justification for war—land was disputed and U.S. soldiers provoked Mexican aggression
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Lincoln, elected to Congress from Illinois as a Whig after war began: “We charge the president with usurping the war-making
power, . . . with seizing a country, . . . which had been for centuries, and was then in the possession of the Mexicans. . . . Let us
put a check upon this lust of dominion. We had territory enough, Heaven knew.”
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Henry David Thoreau penned “Civil Disobedience” and was jailed after refusing to pay taxes that would fund the war effort
2.
Are you surprised by Lincoln’s perspective? Why or why not? Do you think he was right? Why or why not?
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The Wilmot Proviso, 1846
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The question of what to do with new lands acquired from Mexico, assuming the U.S. won the war,
caused controversy from the start
Summary from ushistory.org
By the standards of his day, David Wilmot could be considered a racist. Yet the Pennsylvania
representative was so adamantly against the extension of slavery to lands ceded by Mexico, he made a
proposition that would divide the Congress. On August 8, 1846, Wilmot introduced legislation in the
House that boldly declared, "neither slavery nor involuntary servitude shall ever exist" in lands won in the Mexican-American War. If
he was not opposed to slavery, why would Wilmot propose such an action? Why would the north, which only contained a small, but
growing minority, of abolitionists, agree?
Wilmot and other northerners were angered by President Polk. They felt that the entire Cabinet and national agenda were
dominated by southern minds and southern principles. Polk was willing to fight for southern territory, but proved willing to
compromise when it came to the north. Polk had lowered the tariff, denied funds for internal improvements, and compromised in
Oregon with Britain, all to the dismay of northerners. Now they felt a war was being fought to extend the southern way of life. The
term “slave power” jumped off the lips of northern lawmakers when they angrily referred to their southern colleagues. It was time
for northerners to be heard.
Though Wilmot's heart did not bleed for the slave, he envisioned new territories gained from Mexico as a place where free white
Pennsylvanians could work without the competition of slave labor. Since the north was more populous and had more
Representatives in the House, the Wilmot Proviso passed. Laws require the approval of both houses of Congress, however. The
Senate, equally divided between free states and slave states could not muster the majority necessary for approval. Angrily the House
passed Wilmot’s Proviso several times, all to no avail. It would never become law.
For years, the arguments for and against slavery were debated in the churches and in the newspapers. The House of Representatives
had passed a gag rule (1836-’44) forbidding the discussion of slavery for much of the previous decade. The issue could no longer be
avoided.
3.
What was the [failed] Wilmot Proviso? Why would Northern “racists” support it?
4.
The proviso was originally proposed in 1846, at the beginning of the war. What does that suggest about how American’s
perceived this war and what its outcome would be?
Treaty of Guadalupe Hidalgo, 1848
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Enlarged U.S. population by 1/3
Mexico agreed to Rio Grande border for Texas
U.S. paid $15 million for Mexican cession
Other war costs:
o War cost 97 million U.S. dollars
o Cost 13,000 U.S. lives and 50,000 Mexican lives
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5.
Based on the evidence provided here, was the Mexican-American War “worth it”? Why or why not?
Perspectives on the Treaty
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Debate over whether the treaty went far enough
Racism ultimately ensured Mexican sovereignty
•
President Polk
Polk reluctantly accepted
(wanted “All Mexico!”);
Americans had taken Mexico
City! (see image below)
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Northern Whigs
Southerners
Both supported
Nervous about expanding further into Mexico: would “poison the U.S.,” plus
the U.S. would have to offer territorial governments, which Mexicans
“weren’t capable of”
6.
What is meant by the statement “racism ultimately ensured Mexican
sovereignty”?
7.
Was Polk right? Should we have taken “all of Mexico”? Why or why not?
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