Or if any civil posse, armed or unarmed, enter into any Territory of the United States, under the protection of the laws thereof, with intent to seize individuals, to be carried elsewhere for trial for alleged offenses, and this posse be too powerful to be resisted by the local civil authorities, such seizure or attempt to seize is to be prevented or resisted by the authority of the United States.

The grave and important question now arises whether there be in the Territory of New Mexico any existing law of the United States opposition to which or the obstruction of which would constitute a case calling for the interposition of the authority vested in the President.

The Constitution of the United States declares that—­

This Constitution, and the laws of the United States which shall be made in pursuance thereof, and all treaties made, or which shall be made, under the authority of the United States, shall be the supreme law of the land.

If, therefore, New Mexico be a Territory of the United States, and if any treaty stipulation be in force therein, such treaty stipulation is the supreme law of the land, and is to be maintained and upheld accordingly.

In the letter to the governor of Texas my reasons are given for believing that New Mexico is now a Territory of the United States, with the same extent and the same boundaries which belonged to it while in the actual possession of the Republic of Mexico, and before the late war.  In the early part of that war both California and New Mexico were conquered by the arms of the United States, and were in the military possession of the United States at the date of the treaty of peace.

By that treaty the title by conquest was confirmed and these territories, provinces, or departments separated from Mexico forever, and by the same treaty certain important rights and securities were solemnly guaranteed to the inhabitants residing therein.

By the fifth article of the treaty it is declared that—­

The boundary line between the two Republics shall commence in the Gulf of Mexico 3 leagues from land, opposite the mouth of the Rio Grande, otherwise called Rio Bravo del Norte, or opposite the mouth of its deepest branch if it should have more than one branch emptying directly into the sea; from thence up the middle of that river, following the deepest channel where it has more than one, to the point where it strikes the southern boundary of New Mexico; thence westwardly, along the whole southern boundary of New Mexico (which runs north of the town called Paso) to its western termination; thence northward along the western line of New Mexico until it intersects the first branch of the river Gila (or, if it should not intersect any branch of that river, then to the point on the said line nearest to such branch, and thence in a direct line to the same); thence down the middle of the said branch and of the said river until it empties into the Rio Colorado; thence across the Rio Colorado, following the division line between Upper and Lower California, to the Pacific Ocean.

The eighth article of the treaty is in the following terms: