After the joint resolution for the annexation of Texas to the United States had been passed by our Congress the Mexican minister at Washington addressed a note to the Secretary of State, bearing date on the 6th of March, 1845, protesting against it as “an act of aggression the most unjust which can be found recorded in the annals of modern history, namely, that of despoiling a friendly nation like Mexico of a considerable portion of her territory,” and protesting against the resolution of annexation as being an act “whereby the Province of Texas, an integral portion of the Mexican territory, is agreed and admitted into the American Union;” and he announced that as a consequence his mission to the United States had terminated, and demanded his passports, which were granted.  It was upon the absurd pretext, made by Mexico (herself indebted for her independence to a successful revolution), that the Republic of Texas still continued to be, notwithstanding all that had passed, a Province of Mexico that this step was taken by the Mexican minister.

Every honorable effort has been used by me to avoid the war which followed, but all have proved vain.  All our attempts to preserve peace have been met by insult and resistance on the part of Mexico.  My efforts to this end commenced in the note of the Secretary of State of the 10th of March, 1845, in answer to that of the Mexican minister.  Whilst declining to reopen a discussion which had already been exhausted, and proving again what was known to the whole world, that Texas had long since achieved her independence, the Secretary of State expressed the regret of this Government that Mexico should have taken offense at the resolution of annexation passed by Congress, and gave assurance that our “most strenuous efforts shall be devoted to the amicable adjustment of every cause of complaint between the two Governments and to the cultivation of the kindest and most friendly relations between the sister Republics.”  That I have acted in the spirit of this assurance will appear from the events which have since occurred.  Notwithstanding Mexico had abruptly terminated all diplomatic intercourse with the United States, and ought, therefore, to have been the first to ask for its resumption, yet, waiving all ceremony, I embraced the earliest favorable opportunity “to ascertain from the Mexican Government whether they would receive an envoy from the United States intrusted With full power to adjust all the questions in dispute between the two Governments.”  In September, 1845, I believed the propitious moment for such an overture had arrived.  Texas, by the enthusiastic and almost unanimous will of her people, had pronounced in favor of annexation.  Mexico herself had agreed to acknowledge the independence of Texas, subject to a condition, it is true, which she had no right to impose and no power to enforce.  The last lingering hope of Mexico, if she still could have retained any, that Texas would ever again become one of her Provinces, must have been abandoned.