Thornton’s Luck Cover

Thornton’s Luck

How America Almost Lost the Mexican-American War

Lamont Wood

Rowman & Lone Star Books, Guilford, Connecticut, 2017, 192 pages

Book Review published on: February 22, 2019

History demonstrates that a single event can draw nations into war. The 1914 Sarajevo assassination of the Austrian Archduke Franz Ferdinand, the catalyst for the start of the First World War, is one example. Lamont Wood’s Thornton’s Luck explores another event that occurred sixty-eight years earlier and was the catalyst for war between the United States and Mexico. Historians refer to this single event as the “Thornton Affair.”

Lamont Wood’s extensive research of the war’s historical records and use of original court transcripts and testimonies, provide the reader with insight into five critical areas: (1) the diplomatic failures of both nations that led them to war; (2) the character and behavior of the book’s central character, Capt. Seth B. Thornton; (3) the events of the disastrous Thornton-led patrol; (4) an examination of the four Thornton courts-martial; and (5) a defense of how the Thornton Affair set conditions for a U.S. victory. Of special interest, Woods devotes sixty-four pages to the original testimonies and transcripts of Thornton’s four hearings. These documents allow the reader to get a sense of how Thornton viewed himself and how differently superiors, peers, and subordinates viewed him.

President James K. Polk’s manifest destiny sought the expansion of U.S. territory westward. Despite U.S. efforts to negotiate the purchase of disputed Texas territories, U.S.-Mexico diplomatic relations became strained. Once Texas gained statehood in 1846, Mexico severed diplomatic relations with the United States, threatening to go to war over the disputed territories and the border between the two nations. In order to demonstrate U.S. resolve, Polk directed Brevet Gen. Zachary Taylor and his four thousand-man Army of Occupation to the disputed southern border, land located between the Nueces and Rio Grande Rivers. Mexico considered the U.S. troop movement an act of aggression and sent Gen. Mariano Arista with five thousand troops across the Rio Grande to counter the United States’ action.

The “Thornton Affair” occurred as a result of Taylor’s need to “see if, where, and how many Mexican forces crossed into U.S. territory.” On 25 April 1846, he directed Capt. Thornton to lead a fifty-six-man patrol up the Rio Grande with instructions to “examine the country, move with utmost caution, keep out advanced and flank guards, and take the greatest care not to be drawn into an ambush.” In spite of Taylor’s guidance, a large Mexican cavalry force (estimated at five hundred) surprised and ambushed Thornton’s patrol at a plantation near Rancho de Carricitos (present-day Brownsville, Texas). Seventeen of the severely outnumbered U.S. troopers were killed or wounded during the ambush. Woods attributes this incident to a combination of factors: trooper fatigue, confusion, and the distrust and miscommunication between Thornton and his second-in-command, Capt. William Hardee. Col. David Twiggs, the regimental commander, convened a general court-martial to determine cause and fault. The court acquitted Thornton of the charges against him, conceding that “despite errors of judgement, Thornton took the necessary and customary precautions in the performance of his duties.” Two weeks later on 13 May 1846, the U.S. Congress used the “slaughter of American troops” as justification to declare war against Mexico.

Woods describes Thornton, a veteran of the Second Seminole War, as a “small and sickly man in appearance, who was fundamentally at odds with authority and the center of chaos … one who learned to counter bad luck with stubbornness.” Woods suggests that Thornton’s stubbornness is what kept him in the Army despite a near-death experience aboard an exploding steamer, a duel with a superior officer, the ill-fated patrol, and four courts-martial (twice prior to the war’s start and twice during the war). Not surprising, given Thornton’s demonstrated behavior, the hearings entailed similar charges such as “conduct unbecoming of an officer and a gentlemen, conduct prejudicial to good order and military discipline, expressing disrespect to a superior officer, disobedience of orders, negligence of duty, and breach of arrest.” The most serious charges included “being drunk while in pursuit of the enemy and mutinous conduct.” Although found guilty of many of these charges, the courts’ sentences were so forgiving that none had significant consequence to his Army career that ended on 18 August 1847. While leading a dragoon charge against a Mexican fortification five miles outside Mexico City, Thornton, age thirty-two, was killed when a “Mexican-fired 18-pound cannonball hit him square in the chest killing him outright.”

I recommend adding Lamont Woods’ Thornton’s Luck to your military history library. Within the backdrop of the Mexican-American War, Woods introduces us to a relatively unknown soldier whose actions became the catalyst for our nation’s decision to wage war against our southern neighbor. Suggested by the book’s subtitle, How America Almost Lost the Mexican-American War, Woods effectively portrays how strategically unprepared the U.S. was for war at the time, and how by accident, Thornton’s disastrous patrol provided the nation sufficient warning and awareness to properly resource the U.S. Army and defeat Mexico. At his 1846 court-martial, Thornton defended the success of his expedition as “his encounter with Mexican forces alerted General Taylor to the dangers facing the army, providing him time to prepare and respond appropriately … not knowing could end in a bloody defeat.” Woods effectively summarizes, “the primary thing Taylor learned from the Thornton Affair was that the Mexicans would fight and must be defeated.” The “Thornton Affair” not only gave the United States justification to declare war against Mexico but also time to prepare fortifications, secure lines of communications, and increase and train the Army, enabling it to successfully attack and defeat the Mexican forces. The 1848 Treaty of Guadalupe Hidalgo ended the two-year war with two major U.S. “wins.” The treaty ceded 525,000 square miles of Mexican territory to the United States and recognized the Rio Grande River as the U.S.–Mexico border. It is ironic that Woods’ book provides great insights into the establishment of a border that once again demands the presence of U.S. Army forces.

Book Review written by: James D. Sharpe, Fort Gordon, Georgia