Correspondence Of James K. Polk, Vol. 10

   In the second half of 1845 the focus of Polk’s correspondence shifted from those issues relating to the formation of his administration and distribution of part patronage to those that would give shape and consequence to his presidency: the admission of Texas, preparation for its defense, restoration of diplomatic relations with Mexico, and termination of joint occupancy of the Oregon Country. For the most part the incoming letters tended to urge rather more militancy on the Texas and Oregon questions than Polk would adopt, and notions of national destiny registered a singular theme of buoyant confidence in taking on both Mexico and Great Britain if military action should be required. President Polk and Secretary of State James Buchanan succeeded in both using and controlling the surge of nationalism that heightened expectations for expansion westward.
   Polk and Buchanan agreed on the importance of reestablishing diplomatic relations with Mexico, but the President chose to take a personal hand in managing the selection and instruction of John Slidell, whose departure for Vera Cruz would not be made public until he had arrived in Mexico. Polk wanted to give the fledgling Mexican administration of Jose` Joaqui`n Herrera a chance to compose Mexico’s differences with Washington free of contrary pressures from Great Britain and France; and he fully understood the price that Herrara might pay for a peaceful settlement of the Texas question. If Mexico required more than $6 million for the purchase of their two most northern provinces, as provided in his instructions, Slidell might agree to any reasonable additional sum.
   Slidell’s mission probably never had much chance of success, for without control of his military the Herrara administration could neither give up its claim to Texas nor overcome British opposition to the sale of New Mexico and Upper California. Within but a few days of Slidell’s arrival in the Mexican capital, Mariano Paredes y Argilla organized a military coup, put the Herrera government to flight, and on January 2, 1846, declared himself interim of president of Mexico.
  Polk left on the table his predecessor’s initiative to divide the Oregon Country at the 49th parallel with all of Vancouver Island going to the British. The summary rejection of that offer by the British minister to...