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).


Ulysses S. Grant, Personal Memoirs (New York: Charles Webster and Company, 1894), 37-40.


There was no intimation given that the removal of the 3rd and 4th regiments of infantry to the western border of Louisiana was occasioned in any way by the prospective annexation of Texas, but it was generally understood that such was the case. Ostensibly, we were intended to prevent filibustering1 into Texas, but really as a menace to Mexico in case she appeared to contemplate war. Generally, the officers of the army were indifferent to whether the annexation was consummated or not; but not so all of them. For myself, I was bitterly opposed to the measure, and to this day regard the war, which resulted, as one of the must unjust ever waged by a stronger against a weaker nation. It was an instance of a republic following the bad example of European monarchies, in not considering justice in their desire to acquire more territory.

Texas was originally a state belonging to the republic of Mexico. It extended from the Sabine River on the east to the Rio Grande on the west, and from the Gulf of Mexico on the south and east to the territory of the United States and New Mexico – another Mexican state at that time – on the north and west. An empire in territory, it had but a very sparse population, until settled by Americans who had received authority from Mexico to colonize. These colonists paid very little attention to the supreme government, and introduced slavery into the state almost from the start, though the constitution of Mexico did not, nor does it now, sanction that institution. Soon they set up an independent government of their own, and war existed, between Texas and Mexico, in name from that time until 1836, when active hostilities very nearly ceased upon the capture of Santa Anna, the Mexican President. Before long, however, the same people – who with permission of Mexico had colonized Texas, and afterwards set up slavery there, and then seceded as soon as they felt strong enough to do so – offered themselves and the State to the United States, and in 1845 their offer was accepted. The occupation, separation, and annexation were, from the inception of the movement to its final consummation, a conspiracy to acquire territory out of which slave states might be formed for the American Union.

Even if the annexation itself could be justified, the manner in which the subsequent war was forced upon Mexico cannot. The fact is, annexationists wanted more territory than they could possibly lay any claim to, as part of the new acquisition. Texas, as an independent State, never had exercised jurisdiction over the territory between the Nueces River and the Rio Grande. Mexico had never recognized the independence of Texas, and maintained that, even if independent, the State had no claim south of the Nueces. I am aware that a treaty, made by the Texans with Santa Anna while he was under duress, ceded all the territory between the Nueces and the Rio Grande; but he was a prisoner of war when the treaty was made, and his life was in jeopardy. . . .

In taking military possession of Texas after annexation, the army of occupation, under General Taylor, was directed to occupy the disputed territory. The army did not stop at the Nueces and offer to negotiate for a settlement of the boundary question, but went beyond, apparently in order to force Mexico to initiate war. It is to the credit of the American nation, however, that after conquering Mexico, and while practically holding the country in our possession, so that we could have retained the whole of it, or made any terms we chose, we paid a round sum for the additional territory taken; more than it was worth, or was likely to be, to Mexico. To us it was an empire and of incalculable value; but it might have been obtained by other means. The Southern rebellion was largely the outgrowth of the Mexican war. Nations, like individuals, are punished for their transgressions. We got our punishment in the most sanguinary and expensive war of modern times. . . .

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?

Footnotes

  1. unauthorized action by Americans to foment revolution in South American countries