United States.  They knew, too, that they had no authority to alter or modify the treaty in the form in which it had been ratified by the United States, but that, if failing to procure the ratification of the Mexican Government otherwise than with amendments, their duty, imposed by express instructions, was to ask of Mexico to send without delay a commissioner to Washington to exchange ratifications here if the amendments of the treaty proposed by Mexico, on being submitted, should be adopted by the Senate of the United States.

I was equally well satisfied that the Government of Mexico had agreed to the treaty as amended by the Senate of the United States, and did not regard the protocol as modifying, enlarging, or diminishing its terms or effect.  The President of that Republic, in submitting the amended treaty to the Mexican Congress, in his message on the 8th day of May, 1848, said: 

If the treaty could have been submitted to your deliberation precisely as it came from the hands of the plenipotentiaries, my satisfaction at seeing the war at last brought to an end would not have been lessened as it this day is in consequence of the modifications introduced into it by the Senate of the United States, and which have received the sanction of the President. ...  At present it is sufficient for us to say to you that if in the opinion of the Government justice had not been evinced on the part of the Senate and Government of the United States in introducing such modifications, it is presumed, on the other hand, that they are not of such importance that they should set aside the treaty.  I believe, on the contrary, that it ought to be ratified upon the same terms in which it has already received the sanction of the American Government.  My opinion is also greatly strengthened by the fact that a new negotiation is neither expected nor considered, possible.  Much less could another be brought forward upon a basis more favorable for the Republic.

The deliberations of the Mexican Congress, with no explanation before that body from the United States except the letter of the Secretary of State, resulted in the ratification of the treaty, as recommended by the President of that Republic, in the form in which it had been amended and ratified by the United States.  The conversations embodied in the paper called a protocol took place after the action of the Mexican Congress was complete, and there is no reason to suppose that the Government of Mexico ever submitted the protocol to the Congress, or ever treated or regarded it as in any sense a new negotiation, or as operating any modification or change of the amended treaty.  If such had been its effect, it was a nullity until approved by the Mexican Congress; and such approval was never made or intimated to the United States.  In the final consummation of the ratification of the treaty by the President of Mexico no reference is made to it.  On the contrary, this ratification, which was delivered to the commissioners of the United States, and is now in the State Department, contains a full and explicit recognition of the amendments of the Senate just as they had been communicated to that Government by the Secretary of State and been afterwards approved by the Mexican Congress.  It declares that—­