Introduction

In the early nineteenth century, many “second sons” of slave-holding families (who would not inherit the family plantations) moved west into the Mexican state of Texas, where land was plentiful and well suited for many of the same cash crops as were grown in other parts of the American South. Although these settlers were at first welcomed by the Mexican government, when the country abolished slavery in 1829, they instigated an independence movement that quickly escalated into a war. In 1836, after the Battle of San Jacinto, Mexico recognized Texas as an independent republic; yet tensions remained between the two nations over the disputed territory between the Nueces River and the Rio Grande, some 150 miles to the south.

When the United States agreed to the annexation of Texas in 1845, it also adopted the Rio Grande as the border, leading to a break in diplomatic relations with Mexico and, eventually, to Democratic President James K. Polk’s request for a war declaration in 1847. Polk asserted that the Mexican army had attacked on American soil; skeptical Whigs, including the freshman congressman from Illinois, Abraham Lincoln, questioned the veracity of Polk’s claim. Lincoln and his political compatriots accused Polk of illegitimately escalating a conflict over disputed territory for the sole purpose of extending slave territory. Indeed, Lincoln presented a series of resolutions on the floor of Congress, challenging Polk to identify the very spot where the alleged Mexican attack had occurred and to prove that it was, in fact, on America soil. The “spot resolutions,” as they became known, showcase Lincoln’s famous wit, but with a degree of acerbity that ultimately proved fatal to Lincoln’s career in the House, as Democrats charged him with being unpatriotic, unsupportive of the Army, and even disloyal.

Lincoln’s senior colleague, Henry Clay, also opposed the war publicly, but since his son fought and died in the battle of Vera Cruz, the Democratic press regularly portrayed Clay as two-faced and his opposition as insincere and politically motivated. In “The Great Speech of Clay,” one political cartoon with this trope, Clay’s anti-war audience (to the right) includes Horace Greeley, editor of the New York Tribune, who compares the position of anti-war Whigs with that of the New England Federalists who organized the Hartford Convention. This trope was taken up by at least one member of Congress in a speech haranguing his fellow legislators for their faithlessness to the war effort they had voted to commence only a short time before.

Not all opposition to the war was politically motivated, however: many Northern religious leaders, some of whom were pacifists on principle and some of whom were ardent anti-slavery advocates, freely denounced the war as an act of imperialism and a blatant attempt to increase the territory available to Southern slaveholders. Interestingly, Ulysses S. Grant’s account of the mindset of the troops on the ground in Texas during the conflict supports the latter interpretation (although it is worth noting that the date of Grant’s memoir is significantly after the fact).


John L Magee (presumed), Great speech of Clay – bran bread is riz!!! (N.Y.: Lithograph published by James Baillie, 1847). Library of Congress, Prints and Photographs Division, LC-DIG-ppmsca- 34494.

Study Questions

A. What, exactly, does James K. Polk accuse Mexico of doing in his request for a declaration of war? Why do you think Abraham Lincoln was skeptical of these claims? Would the war seem more or less just depending upon the answers to the questions posed in the spot resolutions? Having once voted to authorize a declaration of war, are congressmen morally obligated, as Andrew Kennedy suggests, to see the thing through to the end, even if they come to see the war as unjust? Was the war with Mexico a legitimate war to protect American territory, or an illegitimate attempt to use federal power to protect and promote the expansion of slavery? Does Ulysses S. Grant’s account seem trustworthy as a reflection of the mindset of the troops on their mission at the time, or does it seem like an example of revisionist history, given his later experiences in the Civil War?

B. How might we connect the anti-war arguments presented here to the abolitionists’ denunciations of armed resistance?

C. In what ways do the arguments for and against the Mexican-American War compare with the arguments for and against the Spanish-American War?