The sagacity of powerful European nations has long since directed their attention to the commercial importance of that Province, and there can be little doubt that the moment the United States shall relinquish their present occupation of it and their claim to it as indemnity an effort would be made by some foreign power to possess it, either by conquest or by purchase. If no foreign government should acquire it in either of these modes, an independent revolutionary government would probably be established by the inhabitants and such foreigners as may remain in or remove to the country as soon as it shall be known that the United States have abandoned it. Such a government would be too feeble long to maintain its separate independent existence, and would finally become annexed to or be a dependent colony of some more powerful state. Should any foreign government attempt to possess it as a colony, or otherwise to incorporate it with itself, the principle avowed by President Monroe in 1824, and reaffirmed in my first annual message, that no foreign power shall with our consent be permitted to plant or establish any new colony or dominion on any part of the North American continent must be maintained. In maintaining this principle and in resisting its invasion by any foreign power we might be involved in other wars more expensive and more difficult than that in which we are now engaged. The Provinces of New Mexico and the Californias are contiguous to the territories of the United States, and if brought under the government of our laws their resources--mineral, agricultural, manufacturing, and commercial--would soon be developed. Upper California is bounded on the north by our Oregon possessions, and if held by the United States would soon be settled by a hardy, enterprising, and intelligent portion of our population. The Bay of San Francisco and other harbors along the Californian coast would afford shelter for our Navy, for our numerous whale ships, and other merchant vessels employed in the Pacific Ocean, and would in a short period become the marts of an extensive and profitable commerce with China and other countries of the East. These advantages, in which the whole commercial world would participate, would at once be secured to the United States by the cession of this territory; while it is certain that as long as it remains a part of the Mexican dominions they can be enjoyed neither by Mexico herself nor by any other nation. New Mexico is a frontier Province, and has never been of any considerable value to Mexico. From its locality it is naturally connected with our Western settlements. The territorial limits of the State of Texas, too, as defined by her laws before her admission into our Union, embrace all that portion of New Mexico lying east of the Rio Grande, while Mexico still claims to hold this territory as a part of her dominions. The adjustment of this question of boundary is important.