The Road to War: The Mexican War
Yesterday I mentioned Texas’ disputed boundary with Mexico. The Texan claim included half of modern New Mexico, the Oklahoma panhandle, a corner of Kansas, a long slice of Colorado, and even a small portion of Wyoming. The Texans never controlled half of it. Their only expedition to extend their authority over New Mexico suffered under Indian raids, got lost, and finally ended up in a Mexican jail.
Mexico considered the Texan claim preposterous, insisting instead on the Nueces River, and threatened war should the United States annex Texas. The US did so on December 29, 1845. James K. Polk, a slaveholder and the only president we know of who traded slaves from within the White House, did not wait for the paperwork. He ordered Zachary Taylor to the Nueces with 3,500 men, close to half of the entire American army at the time. Taylor arrived there in October of 1845.
In November, Polk dispatched John Slidell to Mexico City in secret with an offer to buy California, New Mexico, and settle the border at the Rio Grande in exchange for forgiveness of debts owed to Americans from the Mexican War of Independence to the tune of $3 million (about $71 million today) and offer up $25 million to $30 million (almost $600 million to $713 million) in cash. The Mexicans refused.
Meanwhile, over the winter of 1845-46 federally commissioned explorer John C. Frémont led an armed expedition into Upper California. Frémont insisted he only wanted supplies for a trip up into the Oregon Country. He only entered Californian towns to find a home for his mother, Frémont maintained as he tried to spark an independence-to-annexation movement on the Texas model among local Americans. Smelling a rat, the Mexicans ordered him out. Frémont instead built a fort and ran up the American flag, prompting the local American consul, who was under orders to quietly support a California independence movement, to tell him how his actions undermined those efforts. Frémont left in March, but returned in June to help the Bear Flag Revolt.
Polk ordered Taylor’s army to the Rio Grande in early 1846, where they built a fort facing Matamoros and Taylor attempted negotiations. No one in Taylor’s army had sufficient Spanish and none of the Mexicans facing him had sufficient English, so they negotiated fruitlessly in French. As the standoff progressed, Mexican reinforcements arrived.
On the night of April 24-25, a cavalry detachment of seventy men, tasked to see if the Mexicans had crossed the Rio Grande northwest of the army’s position found out the hard way that two thousand had done just that. After a fight that went on through the night, they surrendered. On receiving the news, Taylor sent word back to Washington that hostilities had commenced. It arrived two weeks later.
With the breaking news in his hand, Polk reported to the Congress that Mexican soldiers invaded American territory and shed American blood. He asked for a declaration of war. On May 13, 1846, the House voted 174-14. The Senate followed 40-2 with fourteen abstaining, eight of those being Northerners. (One other was John C. Calhoun.)
Though popular nationally, the war did not enjoy universal acclaim. Skeptical, a freshman Congressman from Illinois called Polk’s justification “a half insane mumbling of a fever dream.” Lincoln introduced resolutions calling on him to specify the exact spot where Mexicans shed that blood. Of the disputed territory, Lincoln said, “That soil was not ours; and Congress did not annex or attempt to annex it.” Ralph Waldo Emerson agreed, “The United States will conquer Mexico, but it will be as the man swallows the arsenic; Mexico will poison us.”
But Lincoln and Emerson did not represent the majority. War fever swept the nation and, after some early victories, Congress turned to what to do with the vast territories the army would surely take from Mexico.