Excerpt from the Diary of James K. Polk, May 13, 1846 (the day Congress declared war on Mexico)
“Mr. Buchanan said if my views were carried out, we would not settle the Oregon question and we would have war with England.”
Wednesday, 13th May, 1846
…Most of the Cabinet were in attendance, though no Cabinet meeting had been called. A proclamation announcing the existence of the war was prepared and signed by me. This was done in pursuance of the precedent of Mr. Madison, in 1812…Mr. Buchanan read the draft of a despatch which he had prepared to our Ministers at London, Paris, and other foreign courts, announcing the declaration of war against Mexico, with a statement of the causes and objects of the war, with a view that they should communicate its substance to the respective governments to which they are accredited. Among other things Mr. Buchanan had stated that our object was not to dismember Mexico or to make conquests, and that the Del Norte was the boundary to which we claimed; or rather that in going to war we did not do so with a view to acquire either California or New Mexico or any other portion of the Mexican territory.
I told Mr. Buchanan that I thought such a declaration to foreign governments unnecessary and improper; that the causes of the war as set forth in my message to Congress and the accompanying documents were altogether satisfactory. I told him that though we had not gone to war for conquest, yet it was clear that in making peace we would if practicable obtain California and such other portion of the Mexican territory as would be sufficient to indemnify our claimants on Mexico, and to defray the expense of the war which that power by her long continued wrongs and injuries had forced us to wage. I told him it was well known that the Mexican Government had no other means of indemnifying us.
Mr. Buchanan said if when Mr. McLane announced to Lord Aberdeen the existence of the war with Mexico the latter should demand of Mr. McLane to know if we intended to acquire California or any other part of the Mexican territory and no satisfactory answer was given, he thought it almost certain that both England and France would join with Mexico in the war against us. I told him that the war with Mexico was an affair with which neither England, France, nor any other power had any concern; that such an inquiry would be insulting to our government, and if made I would not answer it, even if the consequence should be a war with all of them. I told him I would not tie up my hands or make any pledge to any foreign power as to the terms on which I would ultimately make peace with Mexico. I told him no foreign power had any right to demand any such assurance, and that I would make none such let the consequences be what they might. Then, said Mr. Buchanan, you will have war with England as well as Mexico, and probably with France also, for neither of these powers will ever stand by and see California annexed to the United States.
I told him that before I would make the pledge which he proposed, I would meet the war which either England or France or all the Powers of Christendom might wage, and that I would stand and fight until the last man among us fell in the conflict. I told him that neither as a citizen nor as President would I permit or tolerate any intermeddling of any European Powers on this continent. Mr. Buchanan said if my views were carried out, we would not settle the Oregon question and we would have war with England. I told him there was no connection between the Oregon and Mexican questions, and that sooner than give the pledge he proposed that we would not if we could fairly and honorably acquire California or any other part of the Mexican Territory which we desired, I would let the war which he apprehended with England come and would take the whole responsibility. The Secretary of the Treasury engaged warmly and even in an excited manner against the proposition of Mr. Buchanan in his draft of his despatch. The Secretary of the Navy, the Attorney-General, and the Postmaster-General in succession expressed similar opinions. Mr. Buchanan stood alone in the Cabinet, but was very earnest in expressing his views and enforcing them.
Towards the close of the discussion, which lasted for more than two hours, I stepped to my table and wrote a paragraph to be substituted for all that part of Mr. Buchanan’s proposed despatch which spoke of dismembering Mexico, of acquiring California, or of the Del Norte as the ultimate boundary beyond which we would not claim or desire to go. I strongly expressed to Mr. Buchanan that these paragraphs in his despatch must be struck out. Mr. Buchanan made no reply, but before he left took up his own draft and the paragraphs which I had written and took them away with him. I was much astonished at the views expressed by Mr. Buchanan on the subject. The discussion tonight was one of the most earnest and interesting which has ever occurred in my Cabinet.
SOURCE: Allan Nevins, ed., Polk: The Diary of a President, 1845-1849 (London: Longmans, 1952), 89-91.