A contemporary colored lithograph of the Battle of Buena Vista.

New Mexican and American Commanders

A political storm had broken in Mexico City. In late July, President Paredes, having lost the confidence of the government, abdicated in favor of Vice President Nicholas Bravo. But Bravo’s term of office was short lived: Antonio Lopez de Santa Ana returned from his two-year Cuban exile. On his arrival in Mexico City on 15 September, Gen. J. M. Salas was named acting president and Santa Ana became commander of all Mexican forces.

In Washington, Polk had given Gen. Winfield Scott field command of all forces involved in the war against Mexico. In place of Taylor’s advance from the north, Scott proposed an invasion of central Mexico through the port of Vera Cruz, followed by a direct march on Mexico City. But little happened that fall; desultory peace negotiations continued until 15 November, when Polk rejected the latest Mexican initiative and terminated the process.

In northern Mexico, Taylor’s army had grown to 12,000 men and would soon be joined by Gen. John E. Wool with 2,500 volunteers and newly raised regulars. As soon as the peace negotiations ended, Taylor moved forward and occupied Saltillo and Parras. Elements of the army moved southeast to occupy Victoria and support the Navy’s seizure of Tampico. He was preparing to continue his advance south when Scott arrived in January.

But Taylor’s part in the invasion of Mexico was about to end. Polk was extremely unhappy with him over the terms of the Monterrey surrender, and undoubtedly recognized the potential political risk if Taylor gained any more success. Polk’s backing of Scott’s Vera Cruz plan thus was not based exclusively on military reasoning.

Shortly after his arrival in northern Mexico, Scott departed, taking with him 9,000 of Taylor’s men, including most of the regulars and experienced volunteers. To hold the conquered provinces, Taylor was left with only about 6,000 men, mostly untried volunteers. Those he concentrated south of Saltillo, where he could best intercept any Mexican force sent against him, and from where he could resume his offensive to the south.

Santa Ana had not been idle in the intervening months – the peace negotiations were primarily aimed at gaining time. Ampudia was ordered to bring his remnants to San Luis Potosi, where they were consolidated into the new National Army of nearly 23,000 men. With a large army in place and his political base secure, Santa Ana waited for an opportunity to strike back.

That occurred in dramatic fashion on 13 January 1847, when an American courier was lassoed and killed. The dispatches he carried detailed the proposed operations of Taylor and Scott, including the forces in their respective commands. Santa Ana realized he could defeat the much smaller and widely separated American armies in detail; first Taylor’s at Saltillo, then Scott’s on the coast. On 28 January 1847 the Mexican army moved north.