[203]
Some senators opposed the treaty because they wanted to take no Mexican territory; others hesitated because of the irregular nature of Trist's negotiations. Polk waited in suspense for two weeks as the Senate considered it, sometimes hearing that it would likely be defeated and that Buchanan and Walker were working against it. He was relieved when the two Cabinet officers lobbied on behalf of the treaty. On March 10, the Senate ratified the treaty in a 38–14 vote, on a vote that cut across partisan and geographic lines.[204] The Senate made some modifications to the treaty before ratification, and Polk worried that the Mexican government would reject them. On June 7, Polk learned that Mexico had ratified the treaty.[205] Polk declared the treaty in effect as of July 4, 1848, thus ending the war.[206] With the acquisition of California, Polk had accomplished all four of his major presidential goals.[205] With the exception of the territory acquired by the 1853 Gadsden Purchase, and some later minor adjustments, the territorial acquisitions under Polk established the modern borders of the Contiguous United States.