The personalities shaped the war from the U.S. side: President James Polk, General Zachary Taylor, and General Winfield Scott. Both generals had political potentials, ambitions, and aspirations - to varying degrees. Polk was anxious to minimize the amount of direction competition which the two general could pose for him, and to influence the outcome of their political competition with each other.
Winfield Scott already had a long and distinguished military career behind him when the war started. In 1810, as an officer in the U.S. Army, he had been falsely accused of dishonorable conduct. Historian Brion McClanahan writes:
Scott was forced out of the army for a year. He continued his studies, immersing himself in military strategy. The knowledge he acquired at this time would serve him well during his sixty-three-year career, forty-seven of which years he served as general. When the War of 1812 began, Scott was in New Orleans. He immediately left for Washington, was promoted to lieutenant-colonel, and was transferred to Philadelphia and then to New York to take part in the defense of that state and possibly an invasion of Canada.
While Winfield Scott had an integrated personality and a psychological resilience which allowed him to endure setbacks, the nation of Mexico was, during the first half of the nineteenth century, internally fractured. The country had claimed its independence from Spain in 1821. In the decades before and after that war of independence, historian Irving Levinson informs us, Mexico was divided into a collection of demographic groupings:
Florescano, the preeminent modern historian of this period, characterized the colony as “a disintegrated mosaic of contrasting peoples, ethnic groups, languages, and cultures, disseminated in an extensive territory with poor communication.”
The attainment of independence did not create a sense of national unity. The Mexicans used the term criollo to designate an individual of Spanish ancestry who was born in Mexico. Not only were the criollos one separate group among many, but they were not internally united.
Mexico’s War of Independence did not change this situation. That conflict ended in 1821 with the criollos firmly in control of the newly independent state. This minority divided into two factions.
The questions splitting the criollos were about suffrage, religion, and the power of the government. What degree of freedom would the Mexicans receive? One segment of the criollos
favored the preservation of the colonial social structure, a state religion, very limited suffrage, and a centralized federal regime dominated by the landed and the wealthy.
At stake was whether the Mexicans would merely exchange the oppression of the Spanish crown for a local tyranny, or whether individual political liberty would triumph. If the Mexican government could be structured so that it did not interfere in the markets, and did not burden the people with taxes, then Mexico would have a chance at those benefits which are bundled together under the title of the “New World.”
The other segment of the criollos, Irving Levinson tells us,
opposed all of these objectives and, to varying degrees, sought a more open and egalitarian society. For much of the period from 1821 to 1846, the traditionalists remained in control and emphatically rejected such contemporary Spanish concepts as universal male suffrage. During the 1820s, less than 1 percent of Mexico City’s estimated population of 200,000 owned the property necessary to qualify as voters.
This internally divided nation declared war on the United States in April 1846. By May of that year, the United States had declared war on Mexico. The question at hand was the exact boundary line between Texas and Mexico, and about the ownership of lands which would eventually be parts of Arizona, California, and New Mexico.
Into the mix of personalities on U.S. side entered William Wallace Smith Bliss, a man of exceptional intellect. A brilliant professor of mathematics, he was also gifted in linguistics, and had learned to speak several different Native American (“Indian”) languages. On the political side, he would also eventually marry Zachary Taylor’s daughter after the war, and after Taylor had become president.
Bliss’s intelligence and his political familial connections seemed to destine him for greatness or fame, but he died in 1853 of yellow fever at the age of 37.
Two factors seem to ensure that Zachary Taylor made a reasonable showing in the war: William Bliss, and Taylor’s horse, Old Whitey. Historians Allan Millett and Peter Maslowski write:
Although Polk had no military experience, he acted not only as commander in chief but also as coordinator in chief for the war effort. In the country’s first example of prewar strategic planning, after consulting with his cabinet Polk had contingency war plans drafted more than six month before Arista’s cavalry attacked Taylor’s dragoons north of the Rio Grande. Once the war began he exercised tight control over every aspect of it, setting precedents that subsequent presidents built upon to make the White House, not the Capitol, the center of wartime authority. No problem perplexed Polk as much as the senior Army commanders, Scott and Taylor, who were as different as their nicknames implied. “Old Rough and Ready” Taylor rarely wore a uniform and had limited strategic or tactical ability. His interest in military intelligence and planning for campaigns was deficient that Scott assigned Captain William W.S. Bliss as his chief staff officer. Considered the Army’s brightest intellect, “Perfect” Bliss would compensate for Taylor’s own conception of warfare, which rarely went beyond marching, firing, and charging. Taylor’s strength was his battlefield imperturbability. Sitting atop Old Whitey, one leg crossed over the pommel, and chewing on a straw, he never panicked. “Old Fuss and Feathers” Scott, who became the commanding general in 1841, loved fancy uniforms and had considerable strategic and tactical abilities. Although not a West Pointers, he had a keen interest in military affairs, read widely on the subject, and wrote tactical manuals. A meticulous planner, he insisted upon a thorough military reconnaissance before maneuvering or fighting.
Observers typically report that General Winfield Scott was the more gifted military leader of the two, although Taylor was not without some merit. Scott more than Taylor brought about Mexico’s defeat.
On the Mexican side, the leadership had been desperate enough allow General Santa Anna, who’d been exiled, to return in hopes that he’d lead the Mexican military to a victory over the United States. To the Mexicans he promised that he’d abandoned the political ambitions which had led to his exile; to the United States he secretly promised that he’d betray Mexico and cede the disputed lands to the U.S. once he’d taken control of the Mexican government.
Once back in Mexico, he violated his promise not to seek power and declared himself president. He also violated his promise to the United States and led the Mexican military against it.
The strategy developed for the U.S. forces was that Taylor would have an army on the northeastern border of Mexico, maintaining a presence there to keep some percentage of the Mexican military occupied. Scott would take another army, on ships, south across the Gulf of Mexico, and make an amphibious landing on the southern end of Mexico’s east coast, fighting inland toward Mexico City.
A few smaller units of the U.S. Army would be active along Mexico’s northwestern border.
Taylor, however, was not content to be merely a presence or a diversion. He insisted on advancing his army further into Mexican territory. Historian Russell Weigley writes:
Plunging into Mexico to Monterrey and beyond for strategically dubious purposes, General Taylor mismanaged his logistics so that his troops were too often sick and supply too often uncertain, allowed a relatively lax discipline in regard to plundering the inhabitants, fought battles unsubtly and expensively to clear the Mexican army from his path, and after he became angered by the detachment of 4,000 men including nearly all his Regulars for Scott’s campaign, disobeyed Scott’s orders to retreat to a strong defensive line around Monterrey. Instead Taylor placed his remaining troops in a position difficult to defend and dangling on a precarious supply line, eighteen miles south of Saltillo at the hacienda of Agua Nueva. His excuses for this last decision were that he understood Scott’s orders only as advice, and that the Mexican army could not cross the 200 miles of barren country between San Luis Potosi and his position anyway. When General Antonio Lopez de Santa Anna surprised him by marching 20,000 Mexican soldiers across the barren country to attack him, Taylor, now reduced to 5,000 troops, retreated three miles to slightly better position at the hacienda Buena Vista. There he displayed his best and redeeming qualities, by so inspiring his mostly inexperienced army and so skillfully maneuvering its units from one threatened place to another, that he repulsed the Mexicans with 1,500 to 2,000 casualties to about 750 casualties of his own. Buena Vista is a deservedly famous tactical triumph of American arms; but in strategic conception and conduct, Zachary Taylor’s campaign in Mexico was a throwback to the amateurishness of the War of 1812.
It seems, then, that the main threat to Taylor was his own bad judgment and lack of military skill. Yet both Scott and Taylor would emerge as military heroes in popular accounts of the war.
Taylor was nominated by the Whig Party in 1848 and became president. Winfield Scott was nominated by the same party in 1852, but lost the national election.
Zachary Taylor owned numerous slaves, and saw slavery as a political problem to be solved through negotiation. Polk was also a slaveowner. Winfield Scott was a fierce abolitionist, and saw the elimination of slavery as the only possible or acceptable resolution.
One question raised by the war with Mexico was whether this newly acquired land in the United States would be “free” territory or “slave” territory. Although the U.S. won the war with Mexico, it may have fueled, by doing so, the debate which would eventually erupt into the Civil War.