Introduction

Although Mexico ceded 55% of its territory to the United States in 1848, and the American Civil War in 1861 resulted in 620,000 deaths, the tremendous losses of both nations can be traced directly to the results of the Battle of the Alamo in 1836. In 1846–1848, unsettled disputes and claims would be settled once and for all on the battlefields of the Mexican-American War. Next, Washington would witness fierce debates in Congress while determining whether Texas would enter the Union as a free or slave state. Just 13 years after fighting concluded with Mexico, the Northern and Southern states would be entangled in bloody civil war.

If Washington annexes Texas and goes to war with Mexico, it will be a most unrighteous war and these deeds will lead to civil war in the United States, stated Patriot John Quincy Adams during the Texas Revolution in 1836 as he strongly opposed both Texas annexation and war with Mexico. Twenty-five years later his concerns of civil war would unfold as North and South engaged in a contest of ideologies and wills.

From Mexico's point of view, the Americans at the Alamo (February 26, 1836–March 6, 1836) were rebellious foreigners challenging Mexico's sovereignty. They were not valiant men or heroes of some magnificent last stand, but rather a patchwork rebel group trying to usurp the sovereignty of Mexico in an effort to annex, to steal a large swath of its territory. On the other hand, the United States justified its westward expansion during the 1800s as the policy of Manifest Destiny, and the resistance at the Alamo was the just cause of free men withstanding the tyrannical rule of Mexico City. Whereas the Battle of the Alamo was a military defeat for the Americans, it would become a psychological victory and rallying cry for the nation. As results of the Alamo would send shockwaves across the United States, relations with Mexico would remain strained over the next decade. Unsettled border disputes between the two nations would eventually lead to the Mexican-American War (1846–1848), with the defeated Southern neighbor surrendering more than half of its territory as the outcome.

Conclusion

Unlike several other battles during the Texas Revolution, most individuals are only familiar with the single engagement at the Alamo, which then, like now, stirs emotions of both Mexicans and Americans. The Alamo was an American defeat and a Mexican triumph, but politically, it did more for the United States and its appetite to extend the borders of the nation from sea to shining sea than any other event during the century. Without some 200 dead Americans covering the grounds of an unfamiliar mission in San Antonio, it would have been very difficult, if not impossible for the White House to have rallied the nation and its citizens to war against Mexico just ten years later in 1846.

Among the most vocal opponents of the looming war with Mexican was Congressman John Quincy Adams of Massachusetts. Adams had voiced concerns about expanding into Mexican territory in 1836 and again in 1846 by opposing the Mexican–American War and annexation of Texas, stating that both would serve to add new slave territory to the nation and therefore stir the country to civil war. Congressman Adams, whose service to the nation would span more than 50 years and include a single term as President of the United States, had correctly predicted that both events would push the nation into civil war, an armed conflict that would eventually devour some 620,000 Americans.

From unjust to immoral, were the words of who's who in America while challenging the grounds for war with Mexico. While debating whether the United States should go to war, Congressman Abraham Lincoln challenged President James K. Polk by referring to any war with Mexico as immoral, proslavery, and a threat to the nation's republican values. By enlarging the borders of the United States at the expense of any nation would also serve to provoke President Ulysses S. Grant, who had successfully led the Union Army to victory during the American Civil War, to level a stern rebuke at the nation while writing his memoirs in 1885. 

Having fought in the conflict as a lieutenant, U.S. Grant said in 1885 that the Mexican-American War was "one of the most unjust ever waged by a stronger against a weaker nation. It was an instance of a republic following the bad example of European monarchies, in not considering justice in their desire to acquire additional territory." Continuing in Grant's memoirs, he wrote, "I have never altogether forgiven myself for going into that [war]. I do not think there was ever a more wicked war than that waged by the United States on Mexico. I thought so at the time, when I was a youngster, only I had not moral courage enough to resign.” Ulysses S. Grant would rise through the ranks to the position of Union General of the Army before serving as Eighteenth President of the United States.

Seeking any opportunity to severely punish Mexico for what many believed to be the slaughtering of America's finest during the failed coup attempt at the Alamo and for the continual border disagreements that followed the Texas Revolution, Washington would prod and provoke its neighbor until the two nations were engaged in the Mexican-American War. When you remove the results of the Battle of the Alamo, the majority of Americans, having resided much closer to Canada than the Rio Grande, had little interest in a conflict with Mexico. Without the carnage at the Alamo, the fight with Mexico had very little support and likely would have never been fought. But now with a conquered Mexico, the nation would indeed span from sea to shining sea.