The Mexican-American War is one of the most interesting and important conflicts in US history.
For instance, America’s two most populous; states California and Texas would not be in the Union if the United States had lost the Mexican War. In addition, many places we think of as American today only became American because of the Mexican-American War.
Los Angeles, Hollywood, the Grand Canyon, Las Vegas, San Francisco, the Hoover Dam, Dallas, San Antonio, Orange County, the Las Vegas Strip, Silicon Valley, Houston, San Diego, Santa Fe, Phoenix, Reno, the Great Salt Lake, and Salt Lake City were theoretically Mexican territory in 1845. By 1850, all those places were United States territory and remain so today.
The interesting aspects of the Mexican War go far the beyond territory America gained. Some strange and fascinating aspects of the Mexican-American War include:
Mexico went to War for People who did not want to be part of Mexico
Most of the people in the Mexican territory, the United States conquered did not realize they were Mexicans. Instead, most of the inhabitants of the “Mexican territory” North of today’s Southern United States border were Native Americans. Many of those people did not know Mexico existed, or that they were part of it.
Additionally, there were large populations of Mormons and American settlers in some areas of Mexico’s northern territories who did not recognize the Mexican government’s authority over them. Moreover, the British Empire, the United States, and the Russian Empire all had credible claims on some “Mexican territory.”
Thus it is hard to see what Mexico was fighting for.
The United States Went to War for Debt in 1846
One major cause of the Mexican War was the enormous amount of debt that the Republic of Texas owed to American bankers.
Texas won its “independence” from Mexico in 1835. However, Texas had no money and could only pay its bills by borrowing from American, European, and British banks.
Bankers loaned money to Texas because they thought it was full of rich cotton land. By 1844, however, Texas could never pay back all the money its government had borrowed.
To matters worse, the Mexican government refused to recognize Texas’s independence and was trying to reconquer the state. If Mexico; which was broke and in debt to European banks, conquered Texas the bankers could never get paid? Another fear of American bankers was that the British or French governments would seize Texas to collect their banks’ debts.
There was one way for the American bankers to get paid. It was for Texas to join the union as a state. If Texas joined the United States, the federal government could assume the Lone Star Republic’s debts and pay them.
Moreover, the United States’ military power was far greater than Mexico’s. That meant the US military could protect the bankers’ investment. In addition, the US military was powerful enough to scare off British and French imperialists.
The bankers got to work and spread enormous amounts of money around at the 1844 Democratic Convention and on Capitol Hill. At the 1844 Democratic Convention, James K. Polk of Tennessee, who favored Texas annexation, surprised pundits by winning the nomination over popular ex-President Martin Van Buren (D-New York). In November 1844, Polk won an upset victory over the annexation candidate Henry Clay (W-Kentucky).*
As President, Polk sent US Army troops into Texas which made war with Mexico inevitable. The bankers’ investment was safe but the nation was at war. Moreover, the Mexican War was the first time Wall Street used its’ money to change American politics.
Four American Presidents fought in the Mexican War
Four future American presidents served as officers in the Mexican-American War.
Three future U.S. Presidents; General Zachary Taylor (W-Louisiana), Franklin Pierce (D-New Hampshire, and Ulysses S. Grant (R-Illinois), fought in the Mexican-American War. Taylor commanded the US Army that won important victories over the Mexican Army of the North.
Pierce served as a Brigadier General and defeated another Mexican War hero General Winfield Scott in the 1852 presidential election. Grant, a young officer, fought under Taylor’s command in Northern Mexico and Texas.
Moreover, future Confederate President Jefferson Davis (D-Mississippi), served as the colonel of a volunteer regiment in Taylor’s army. Interestingly, Davis was Zachary Taylor’s former son-in-law. Davis’s deceased first life was Taylor’s daughter. Notably, Taylor and Davis were good friends despite serious political differences.
The Mexican-American War almost destroyed Abraham Lincoln’s political career
In 1846, U.S. Representative Abraham Lincoln (W-Illinois) was a rising star in the Whig Party. Lincoln destroyed his career by questioning Polk’s pretext for war – the exact location of a Texas border the president alleged Mexican troops had crossed.
Lincoln’s protest doomed his reelection in 1848. Honest Abe went home to Illinois and spent the next decade as a successful corporate lawyer. Lincoln made a successful political comeback in the late 1850s that led his election as president in 1860.
A Routine Appropriations bill in the Mexican-American War helped cause the US Civil War
On 8 August 1846 US Representative David Wilmot (D-Pennsylvania) added what historians call the Wilmot Proviso to legislation to finance the purchase of Mexican territory.
The Proviso added language from Thomas Jefferson’s Northwest Ordinance of 1787 that banned slavery in conquered Mexican territories to the bill. Wilmot’s action split the US House of Representatives along sectional lines.
Every Northern Representative; both Democrat and Whig, voted for the Proviso. Most Southerners of both parties voted against the Proviso. However, the U.S. Senate stripped the Wilmot Proviso from the Appropriations bill it went to President Polk. To elaborate, under the US Constitution both the House and the Senate have to approve budget legislation.
Wilmot’s action set the stage for the Civil War by convincing many Southerners that Northerners would never let them expand slavery to the territories conquered from Mexico. Those suspicions proved correct in 1850 when President Zachary Taylor (W-Louisiana), ironically a Southerner and a slave owner, and other Whig leaders forced California’s admission to the Union as a free state.*
Another long-term result of the Wilmot Proviso was that antislavery northern Whigs and Democrats left their parties and formed a new organization. That organization became the Republican Party, which is still one of America’s two major political parties.
President Polk did not like the Treaty Ending the Mexican War
In 1847, Polk sent diplomat Nicholas Trist to Mexico City to negotiate an end to the war. Polk sent Trist because he was afraid Whig General Winfield Scott would negotiate a treaty he did not like.
However, Trist and Scott; whose armies were occupying Mexico City, negotiated the treaty Polk did not want. To explain, Polk wanted to seize Mexican lands south of the Rio Grande River. Polk wanted to get land suitable for cotton growing and distribute to wealthy Southern slave owners some of his biggest supporters.
Instead, Trist and Scott realized that Mexican leaders were willing to give lands north of the present US Mexican border away to get American troops out of Mexico. Scott wanted US troops out of Mexico to avoid a deadly guerrilla war he was afraid America could lose.
Thus Trist negotiated and the Mexicans signed the treaty Polk did not want – the Treaty of Guadalupe Hildago. Trist sent the treaty to Washington where the U.S. Senate ratified it ending the war.
Polk got his revenge on Trist by refusing to pay him for his diplomatic work in Mexico. Meanwhile, Scott forced the US to accept the treaty by pulling his army out Mexico.
Trist left the diplomatic service and ended up working as railroad executive for the next few decades. It would be nearly 20 years until Abraham Lincoln’s (R-Illinois) presidency that Congress finally paid Trist for the Treaty of Guadalupe Hidalgo.*
The Southern slave owners never got the cotton lands in Mexico they wanted. Instead, northerners settled most of the lands seized in the Mexican War and formed additional free states.
Many of America’s Civil War Generals Fought Together in Mexico
Most of the men who led the Union and Confederate armies in the U.S. Civil War fought side by side as U.S. Army officers in the Mexican-American War.
Robert E. Lee, Joseph E. Johnston, Ulysses S. Grant, Albert Sidney Johnston, George McClellan, James Longstreet, P.G.T. Beauregard, and Thomas Jonathan “Stonewall” Jackson all served in the Mexican War. Jackson, McClellan, and Lee all won some fame with their Mexican-American War Service. However, Grant did not.
Many Americans opposed the Mexican War
Ulysses S. Grant called the conflict a “wicked war” and speculated that the Civil War was God’s punishment on America for the Mexican Conflict.
Poet and philosopher Ralph Waldo Emerson predicted “Mexico will poison us” when he wrote about the conflict. Notably, Emerson’s friend Henry David Thoreau held one of America’s first peace protests against the Mexican-American War.
On 23 July 1846, authorities in Concord, Massachusetts, jailed Thoreau for refusing to pay the poll tax. Thoreau refused to pay taxes to a government that was waging war for slavery. Thoreau only spent one night in jail because an anonymous benefactor paid his tax.
In 1849, Thoreau wrote a lecture and essay about his antiwar protest that became known as Civil Disobedience. During the 20th Century both Mahatma Gandhi and Dr. Martin Luther King Jr. cited Civil Disobedience as an inspiration for their work.
It is easy to see why many historians regard the Mexican-American War as the beginning of the United States. America would have never become a continent spanning superpower, fought a civil war, or abolished slavery without the Mexican-American War.
*For a good view of the bankers’ role in Texas annexation and California’s admission to the Union see Prologue to Conflict: The Crisis and Compromise of 1850 by Holman Hamilton.
*See The Battle Cry of Freedom: The Civil War Era by James M. McPherson page 50 a good description of Trist’s diplomacy.