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 1846. 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).
James K. Polk, “Special Message to Congress on Mexican Relations,” May 11, 1846. Online by Gerhard Peters and John T. Woolley, The American Presidency Project. https://goo.gl/o9uAFh.
The existing state of the relations between the United States and Mexico renders it proper that I should bring the subject to the consideration of Congress. In my message at the commencement of your present session, the state of these relations, the causes which led to the suspension of diplomatic intercourse between the two countries in March, 1845, and the long-continued and unredressed wrongs and injuries committed by the Mexican Government on citizens of the United States in their persons and property were briefly set forth.
As the facts and opinions which were then laid before you were carefully considered, I cannot better express my present convictions of the condition of affairs up to that time than by referring you to that communication.
The strong desire to establish peace with Mexico on liberal and honorable terms, and the readiness of this Government to regulate and adjust our boundary and other causes of difference with that power on such fair and equitable principles as would lead to permanent relations of the most friendly nature, induced me in September last to seek the reopening of diplomatic relations between the two countries. Every measure adopted on our part had for its object the furtherance of these desired results. In communicating to Congress a succinct statement of the injuries which we had suffered from Mexico, and which have been accumulating during a period of more than twenty years, every expression that could tend to inflame the people of Mexico or defeat or delay a pacific result was carefully avoided. An envoy of the United States repaired to Mexico with full powers to adjust every existing difference. But though present on the Mexican soil by agreement between the two Governments, invested with full powers, and bearing evidence of the most friendly dispositions, his mission has been unavailing. The Mexican Government not only refused to receive him or listen to his propositions, but after a long-continued series of menaces have at last invaded our territory and shed the blood of our fellow-citizens on our own soil. . . .
In my message at the commencement of the present session I informed you that upon the earnest appeal both of the Congress and convention of Texas I had ordered an efficient military force to take a position “between the Nueces and the Del Norte.” This had become necessary to meet a threatened invasion of Texas by the Mexican forces, for which extensive military preparations had been made. The invasion was threatened solely because Texas had determined, in accordance with a solemn resolution of the Congress of the United States, to annex herself to our Union, and under these circumstances it was plainly our duty to extend our protection over her citizens and soil.
This force was concentrated at Corpus Christi, and remained there until after I had received such information from Mexico as rendered it probable, if not certain, that the Mexican Government would refuse to receive our envoy.
Meantime Texas, by the final action of our Congress, had become an integral part of our Union. The Congress of Texas, by its act of December 19, 1836, had declared the Rio del Norte to be the boundary of that Republic. . . . This river, which is the southwestern boundary of the State of Texas, is an exposed frontier. From this quarter invasion was threatened; upon it and in its immediate vicinity, in the judgment of high military experience, are the proper stations for the protecting forces of the Government. In addition to this important consideration, several others occurred to induce this movement. Among these are the facilities afforded by the ports at Brazos Santiago and the mouth of the Del Norte for the reception of supplies by sea, the stronger and more healthful military positions, the convenience for obtaining a ready and a more abundant supply of provisions, water, fuel, and forage, and the advantages which are afforded by the Del Norte in forwarding supplies to such posts as may be established in the interior and upon the Indian frontier.
The movement of the troops to the Del Norte was made by the commanding general under positive instructions to abstain from all aggressive acts toward Mexico or Mexican citizens and to regard the relations between that Republic and the United States as peaceful unless she should declare war or commit acts of hostility indicative of a state of war. He was specially directed to protect private property and respect personal rights. . . .
The Mexican forces at Matamoras assumed a belligerent attitude, and on the 12th of April General Ampudia, then in command, notified General Taylor to break up his camp within twenty-four hours and to retire beyond the Nueces River, and in the event of his failure to comply with these demands announced that arms, and arms alone, must decide the question. But no open act of hostility was committed until the 24th of April. On that day General Arista, who had succeeded to the command of the Mexican forces, communicated to General Taylor that “he considered hostilities commenced and should prosecute them.” A party of dragoons of sixty-three men and officers were on the same day dispatched from the American camp up the Rio del Norte, on its left bank, to ascertain whether the Mexican troops had crossed or were preparing to cross the river, “became engaged with a large body of these troops, and after a short affair, in which some sixteen were killed and wounded, appear to have been surrounded and compelled to surrender.”
The grievous wrongs perpetrated by Mexico upon our citizens throughout a long period of years remain unredressed, and solemn treaties pledging her public faith for this redress have been disregarded. A government either unable or unwilling to enforce the execution of such treaties fails to perform one of its plainest duties.
Our commerce with Mexico has been almost annihilated. It was formerly highly beneficial to both nations, but our merchants have been deterred from prosecuting it by the system of outrage and extortion which the Mexican authorities have pursued against them, whilst their appeals through their own Government for indemnity have been made in vain. Our forbearance has gone to such an extreme as to be mistaken in its character. Had we acted with vigor in repelling the insults and redressing the injuries inflicted by Mexico at the commencement, we should doubtless have escaped all the difficulties in which we are now involved.
Instead of this, however, we have been exerting our best efforts to propitiate her good will. Upon the pretext that Texas, a nation as independent as herself, thought proper to unite its destinies with our own she has affected to believe that we have severed her rightful territory, and in official proclamations and manifestoes has repeatedly threatened to make war upon us for the purpose of reconquering Texas. In the meantime, we have tried every effort at reconciliation. The cup of forbearance had been exhausted even before the recent information from the frontier of the Del Norte. But now, after reiterated menaces, Mexico has passed the boundary of the United States, has invaded our territory and shed American blood upon the American soil. She has proclaimed that hostilities have commenced, and that the two nations are now at war.
As war exists, and, notwithstanding all our efforts to avoid it, exists by the act of Mexico herself, we are called upon by every consideration of duty and patriotism to vindicate with decision the honor, the rights, and the interests of our country.
Anticipating the possibility of a crisis like that which has arrived, instructions were given in August last, “as a precautionary measure” against invasion or threatened invasion, authorizing General Taylor, if the emergency required, to accept volunteers, not from Texas only, but from the States of Louisiana, Alabama, Mississippi, Tennessee, and Kentucky, and corresponding letters were addressed to the respective governors of those States. These instructions were repeated, and in January last, soon after the incorporation of “Texas into our Union of States,” General Taylor was further “authorized by the President to make a requisition upon the executive of that State for such of its militia force as may be needed to repel invasion or to secure the country against apprehended invasion.” On the 2d day of March he was again reminded, “in the event of the approach of any considerable Mexican force, promptly and efficiently to use the authority with which he was clothed to call to him such auxiliary force as he might need.” War actually existing and our territory having been invaded, General Taylor, pursuant to authority vested in him by my direction, has called on the governor of Texas for four regiments of State troops, two to be mounted and two to serve on foot, and on the governor of Louisiana for four regiments of infantry to be sent to him as soon as practicable.
In further vindication of our rights and defense of our territory, I invoke the prompt action of Congress to recognize the existence of the war, and to place at the disposition of the Executive the means of prosecuting the war with vigor, and thus hastening the restoration of peace. To this end I recommend that authority should be given to call into the public service a large body of volunteers to serve for not less than six or twelve months unless sooner discharged. A volunteer force is beyond question more efficient than any other description of citizen soldiers, and it is not to be doubted that a number far beyond that required would readily rush to the field upon the call of their country. I further recommend that a liberal provision be made for sustaining our entire military force and furnishing it with supplies and munitions of war.
The most energetic and prompt measures and the immediate appearance in arms of a large and overpowering force are recommended to Congress as the most certain and efficient means of bringing the existing collision with Mexico to a speedy and successful termination.
In making these recommendations I deem it proper to declare that it is my anxious desire not only to terminate hostilities speedily, but to bring all matters in dispute between this Government and Mexico to an early and amicable adjustment; and in this view I shall be prepared to renew negotiations whenever Mexico shall be ready to receive propositions or to make propositions of her own. . . .