Mexican War, and the Conquest of the American Continent (2009)
On 19 September 1846, the Mexican government rejected Polk's terms on negotiations . . . to Polk, captured land from the Mexican War would now be "captured booty". Mexico's strategy was centered on scoring a significant victory, THEN negotiate with the U.S. from a position of strength. Americans started to realize that the Mexican War would be a protracted conflict, especially when newspapers reported that Santa Anna had boasted that he would drive Taylor back to the Sabine River (the border between Texas and Louisiana). Santa Anna had fooled and deceived Polk, and in Mexico, Santa Anna was free to pursue what he treasured most: ultimate glory and national acclaim.
Taylor showed valor and tactical abilities, but many in the government and military questioned his strategic thinking. Taylor had defeated the larger Mexican force, and was in the process of house-to-house fighting, removing the Mexican army from Monterrey. Near the moment of victory, Taylor let the Mexican general off the hook by agreeing to let his army leave the area. It's possible that Taylor could have ended the war outright by defeating and capturing the largest Mexican army . . . Polk and his Cabinet were furious. But Polk didn't know that Taylor's men were a bedraggled and demoralized lot by the time they reached Monterrey. Taylor was ordered by Polk to ignore his agreement with the Mexican general, and move deeper into Mexico in pursuit.
And then, disaster: due to numerous newspaper accounts, Polk's deal returning Santa Anna to Mexico became public, and the results of the Off-Year Elections of 1846 (30th Congress) would have 115 Whigs to 108 Democrats in the House of Representatives. Henry Clay's Whig party had picked up 31 seats, while the Democrats lost 28, a swing of 59 seats. In the Senate, the Democrats only had a +4 advantage over the Whigs, but the Democrats were not a unified party . . . the Mexican War and the debate on the expansion of slavery (Wilmot Proviso) was the catalyst for the opposition to Polk.
Polk offered the position of Lieutenant General (overall commander of the Army, based in Washington, D.C.) to Senator Thomas Hart Benton (D; MO), who accepted, pending confirmation in Congress. To win the war, Polk now needed to quickly take Veracruz and Mexico City, while at the same time getting a less-than-cooperative Congress to fund all that was required to win the war. Polk authorized the invasion of Mexico at Veracruz, but delayed any decision regarding Mexico City. Polk's Cabinet reluctantly agreed that the vainglorious General Winfield Scott (pictured above; "Old Fuss & Feathers"), was the only choice to command at Veracruz.
Representative Stephen Douglas (pictured, D; Ill), a rising political star, supported Polk, as well as Commander Stockton's and General Kearny's actions in California (However, Stockton and Kearny had granted U.S. citizenship, which only Congress could legally do). The U.S. had never acted like this before with another nation; everything about the Mexican War was new and debatable (e.g. Polk's "Right of Conquest" reference in his 2nd Annual Message was not mentioned anywhere in the Constitution). The "intensifier" of the debate on the war was Polk's "aid and comfort" phrase, which had appeared in most American newspapers.
On 21 December 1846, Polk met with Benton (pictured), informing him that his support in Congress was nowhere-near sufficient for Benton to be confirmed in the newly-created position of Lieutenant General. Benton wanted Polk to press on in his behalf, and Polk wrote out a draft supporting Benton, mostly to keep the powerful Democratic Senator amenable towards his administration. By the end of 1846, most Americans supported expansion West, as well as the Mexican War, but opposition to the war was growing, and becoming more vocal and organized. The Whigs sensed political opportunity in the upcoming Presidential Election of 1848 (already, Zachary Taylor was targeted by many Whigs for their party's nomination), and the creation of the "Free Soil Party" would further intensify the debate on the expansion of slavery in any territories taken from Mexico.