[199] Though outraged by Trist's defiance, Polk decided to allow him some time to negotiate a treaty.[200]
Throughout January 1848, Trist regularly met with officials in Mexico City, though at the request of the Mexicans, the treaty signing took place in Guadalupe Hidalgo, a small town near Mexico City. Trist was willing to allow Mexico to keep Baja California, as his instructions allowed, but successfully haggled for the inclusion of the important harbor of San Diego in a cession of Alta California. Provisions included the Rio Grande border and a $15 million payment to Mexico. On February 2, 1848, Trist and the Mexican delegation signed the Treaty of Guadalupe Hidalgo. Polk received the document on February 19,[201][202] and, after the Cabinet met on the 20th, decided he had no choice but to accept it. If he turned it down, with the House by then controlled by the Whigs, there was no assurance Congress would vote funding to continue the war. Both Buchanan and Walker dissented, wanting more land from Mexico, a position with which the President was sympathetic, though he considered Buchanan's view motivated by his ambition.