JAMES K. POLK.

WASHINGTON, February 8, 1849.

To the House of Representatives of the United States: 

In reply to the resolutions of the House of Representatives of the 5th instant, I communicate herewith a report from the Secretary of State, accompanied with all the documents and correspondence relating to the treaty of peace concluded between the United States and Mexico at Guadalupe Hidalgo on the 2d February, 1848, and to the amendments of the Senate thereto, as requested by the House in the said resolutions.

Amongst the documents transmitted will be found a copy of the instructions given to the commissioners of the United States who took to Mexico the treaty as amended by the Senate and ratified by the President of the United States.  In my message to the House of Representatives of the 29th of July, 1848, I gave as my reason for declining to furnish these instructions in compliance with a resolution of the House that “in my opinion it would be inconsistent with the public interests to give publicity to them at the present time.”  Although it may still be doubted whether giving them publicity in our own country, and, as a necessary consequence, in Mexico, may not have a prejudicial influence on our public interests, yet, as they have been again called for by the House, and called for in connection with other documents, to the correct understanding of which they are indispensable, I have deemed it my duty to transmit them.

I still entertain the opinion expressed in the message referred to, that—­

As a general rule applicable to all our important negotiations with foreign powers, it could not fail to be prejudicial to the public interests to publish the instructions to our ministers until some time had elapsed after the conclusion of such negotiations.

In these instructions of the 18th of March, 1848, it will be perceived that—­

The task was assigned to the commissioners of the United States of consummating the treaty of peace, which was signed at Guadalupe Hidalgo on the 2d day of February last, between the United States and the Mexican Republic, and which on the 10th of March last was ratified by the Senate with amendments.

They were informed that—­

This brief statement will indicate to you clearly the line of your duty.  You are not sent to Mexico for the purpose of negotiating any new treaty, or of changing in any particular the ratified treaty which you will bear with you.  None of the amendments adopted by the Senate can be rejected or modified except by the authority of that body.  Your whole duty will, then, consist in using every honorable effort to obtain from the Mexican Government a ratification of the treaty in the form in which it has been ratified by the Senate, and this with the least practicable delay. ...  For this purpose it may, and most probably will, become