In the Mexican War, the United States lost thirteen thousand men. Based upon the number of troops which we committed to the war, that makes it the bloodiest war in our history. The unexamples heroism of individual American soldiers and entire units stands out as an everlasting testimony to the willingness of American volunteers to trust their government, and give "the last full measure of devotion."
Every American army in Mexico was outnumbered when they fought. With courage and the professionalism of the officer corps, they overcame the discrepancy to win consistently. At Monterrey, Jefferson Davis' volunteers hacked their way through walls of houses using their bayonets and their bare hands, and cleaned out the defenders in the next house before moving on, because to go into the streets swept with Mexican artillery was suicide. At Palo Alto and Resaca de la Palma, American infantry, unsupported, made bayonet charges against dug-in Mexican artillery supported by lancers. At Buena Vista, a two-gun section of American artillery held off the attack of more than four thousand Mexican infantry for more than an hour, defending a gap in Zachary Taylor's lines, until units could be brought up to their support, and to drive back the Mexicans. At Contreras, American artillery of inferior calibre dueled all day with Mexican guns in superior numbers, until all the guns were dismounted or the gun crews too decimated to continue to serve their guns, so that American infantry could cross a steep and dangerous ravine to get on the Mexican flank. That sacrifice lead directly to meeting engagement at Churubusco which sealed the fate of the city of Mexico. At Molino del Rey, because their officers told them to, American infantry and Marines launched themselves in a useless and bloody assault against a heavy fortified and defended Mexican position, and drove superior numbers of the enemy from that position at terrible cost. Winfield Scott acknowledged the same day that he had been wrong, and that the attack wasn't needed. Following Molino del Rey, the Americans assaulted the heavily defended castle at Chapultepec--the Mexican Military Academy--to take down the last Mexican defense outside the city walls. Lieutenant Thomas Jackson took his two gun artillery section through ground so swept with Mexican artillery fire that all of the horses were killed, and most of the gun crews deserted--it was too much for them--and one of the two guns was dismounted. With the help of a sergeant and a handful of gunners he man-handled one gun into position, while his commander, Captain John Magruder, walked into the maelstrom of Mexican artillery fire to drag gunners out of cover by main force, and then re-mount the damaged gun and drag it through the ditches to Jackson. Ordered to retreat, Jackson refused, saying his men would all be killed or wounded if required to cross that ground again. The Mexicans became obsessed with "getting" Jackson, and soon turned every gun they could on his position, where he and his men continued to serve the guns. This crucial action allowed the American "forlorn hope" of infantry and Marines to rush the walls with far fewer casualties, and drive the Mexicans from their position. The Mexican defense collapsed thereafter, and individual Lieutenants and Sergeants lead bands of men they picked up in a rush upon the gates that lead to the evacuation of the capital by Santa Anna, and the final defeat of Mexico.
One of those Lieutenants was "Sam" Grant. Although an infantry officer, and although his unit was not then engaged, he rounded up a sergeant and some infantry men, and remounted a dismounted American howitzer, which they dragged by main force to the top of a church steeple, and used it to sweep the causeway to the San Cosme gate, resulting in the entry of American troops into the city.
This is what Grant has to say about the Mexican War in his memoirs:
There are but few instances in American military history in which professional soldiers and volunteers consistently exhibited such a high order of courage and successful valor on the battlefield--certainly i would contend that there are none in which they were excelled. None of that changes the ugly facts surrounding that war and the outright theft from Mexico of one third of its sovereign territory, largely intend to provide territory from which new slave states could be created.
As Dys cogently observes, that an honorable man die honorably in a war does not make the war honorable.
