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 63 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 16 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.