By the cession of the whole of New Mexico, on both sides of the Rio Grande, to the United States, the question of disputed boundary, so far as Mexico is concerned, has been settled, leaving the question as to the true limits of Texas in New Mexico to be adjusted between that State and the United States.
Under the circumstances existing during the pendency of the war, and while the whole of New Mexico, as claimed by our enemy, was in our military occupation, I was not unmindful of the rights of Texas to that portion of it which she claimed to be within her limits. In answer to a letter from the governor of Texas dated on the 4th of January, 1847, the Secretary of State, by my direction, informed him in a letter of the 12th of February, 1847, that in the President's annual message of December, 1846—
You have already perceived that New Mexico is at present in the temporary occupation of the troops of the United States, and the government over it is military in its character. It is merely such a government as must exist under the laws of nations and of war to preserve order and protect the rights of the inhabitants, and will cease on the conclusion of a treaty of peace with Mexico. Nothing, therefore, can be more certain than that this temporary government, resulting from necessity, can never injuriously affect the right which the President believes to be justly asserted by Texas to the whole territory on this side of the Rio Grande whenever the Mexican claim to it shall have been extinguished by treaty. But this is a subject which more properly belongs to the legislative than the executive branch of the Government.
The result of the whole is that Texas had asserted a right to that part of New Mexico east of the Rio Grande, which is believed, under the acts of Congress for the annexation and admission of Texas into the Union as a State, and under the constitution and laws of Texas, to be well founded; but this right had never been reduced to her actual possession and occupancy. The General Government, possessing exclusively the war-making power, had the right to take military possession of this disputed territory, and until the title to it was perfected by a treaty of peace it was their duty to hold it and to establish a temporary military government over it for the preservation of the conquest itself, the safety of our Army, and the security of the conquered inhabitants.
The resolutions further request information whether any persons have been tried and condemned for "treason against the United States in that part of New Mexico lying east of the Rio Grande since the same has been in the occupancy of our Army," and, if so, before "what tribunal" and "by what authority of law such tribunal was established." It appears that after the territory in question was "in the occupancy of our Army" some of the conquered Mexican inhabitants, who had at first submitted to our authority, broke out in open insurrection, murdering our soldiers and citizens and committing other atrocious crimes. Some of the principal offenders who were apprehended were tried and condemned by a tribunal invested with civil and criminal jurisdiction, which had been established in the conquered country by the military officer in command. That the offenders deserved the punishment inflicted upon them there is no reason to doubt, and the error in the proceedings against them consisted in designating and describing their crimes as "treason against the United States." This error was pointed out, and its recurrence thereby prevented, by the Secretary of War in a dispatch to the officer in command in New Mexico dated on the 26th of June, 1847, a copy of which, together with copies of all communications relating to the subject which have been received at the War Department, is herewith transmitted.
The resolutions call for information in relation to the quantity of the public lands acquired within the ceded territory, and "how much of the same is within the boundaries of Texas as defined by the act of the Congress of the Republic of Texas of the 19th day of December, 1836." No means of making an accurate estimate on the subject is in the possession of the executive department. The information which is possessed will be found in the accompanying report of the Secretary of the Treasury.
The country ceded to the United States lying west of the Rio Grande, and to which Texas has no title, is estimated by the commissioner of the General Land Office to contain 526,078 square miles, or 336,689,920 acres.
The period since the exchange of ratifications of the treaty has been too short to enable the Government to have access to or to procure abstracts or copies of the land titles issued by Spain or by the Republic of Mexico. Steps will be taken to procure this information at the earliest practicable period. It is estimated, as appears from the accompanying report of the Secretary of the Treasury, that much the larger portion of the land within the territories ceded remains vacant and unappropriated, and will be subject to be disposed of by the United States. Indeed, a very inconsiderable portion of the land embraced in the cession, it is believed, has been disposed of or granted either by Spain or Mexico.
What amount of money the United States may be able to realize from the sales of these vacant lands must be uncertain, but it is confidently believed that with prudent management, after making liberal grants to emigrants and settlers, it will exceed the cost of the war and all the expenses to which we have been subjected in acquiring it.
The resolutions also call for "the evidence, or any part thereof, that the 'extensive and valuable territories ceded by Mexico to the United States constitute indemnity for the past.'"