Although Mexico had severed diplomatic relations with the United States in March, 1845 over the annexation of Texas, the Polk administration continued to maintain a dialogue with the Herrera government, having sent William S. Parrott, a former consul, as a confidential agent to Mexico City. On September 16, the administration received an encouraging report from Parrott, which seemed to indicate that Mexico was now ready to restore diplomatic relations and would receive a "Minister" from the United States. Accordingly, Polk decided to send John Slidell to Mexico City, with instructions to negotiate the boundary line between Texas and Mexico, and purchase Upper California and New Mexico.
TUESDAY, 16th September, 1845.--The Cabinet met today, all the members present. Despatche[s] were read from Dr. Parrott, the confidential agent of the U. S. in Mexico, giving an account of another threatened Revolution, & of the refusal of Paredes to march his army to Texas. Dr. Parrott's latest despatch was of date 29th August, 1845. He gives it as his opinion that there will be no declaration of war against the U. S. and no invasion of Texas; that the Government will be kept employed to keep down another revolution which was threatened. He is also of opinion that the Government is desirous to re-establish Diplomatic relations with the U. States, and that a Minister from the U. S. would be received. In these opinions Mr. Black, the U. S. consul at Mexico, of date 23rd Aug't, and Mr. Dimond, U. S. Consul at Vera Cruz, of date 30th Aug't concurred. After much consultation it was agreed unanimously that it was expedient to re-open Diplomatic relations with Mexico; but that it was to be kept a profound secret that such a step was contemplated, for the reason mainly that if it was known in advance in the U. S. that a Minister had been sent to Mexico, it would, of course, be known to the Brittish, French, & other Foreign Ministers at Washington, who might take measures to thwart or defeat the objects of the mission. The President, in consultation with the Cabinet, agreed that the Hon. John Slidell of New Orleans, who spoke the Spanish language and was otherwise well qualified, should be tendered the mission. It was agreed that Mr. Slidell, if he accepted, should leave Pensacola in a National Armed vessel & proceed to Vera Cruz, without disclosing or making known his official character. One great object of the Mission, as stated by the President, would be to adjust a permanent boundary between Mexico and the U. States, and that in doing this the Minister would be instructed to purchase for a pecuniary consideration Upper California and New Mexico. He said that a better boundary would be the Del Norte from its mouth to the Passo, in latitude about 32° North, and thence West to the Pacific Ocean, Mexico ceding to the U. S. all the country East and North of these lines. The President said that for such a boundary the amt. of pecuniary consideration to be paid would be of small importance. He supposed it might be had for fifteen or twenty millions, but he was ready to pay forty millions for it, if it could not be had for less. In these views the Cabinet agreed with the President unanimously.
