Douglas A. Murphy. Two Armies on the Rio Grande: The First Campaign of the US-Mexican War. College Station: Texan A&M University Press, 2014. 320 pp. $45.00 (cloth), ISBN 978-1-62349-189-5.
Reviewed by Samuel Watson (United States Military Academy)
Published on H-War (February, 2022)
Commissioned by Margaret Sankey (Air University)
Examining the battles of Palo Alto and Resaca de la Palma (May 8-9, 1846) and the year before the US-Mexican War began, Douglas Murphy, chief historian and chief of operations at Palo Alto Battlefield National Historical Park, has written the most detailed modern battle and campaign study available for the Mexican-American War. He states up front that “this account follows a path beaten out by many … who have gone before” (p. 10), but Two Armies on the Rio Grande does offer interpretations of the road to war and the reasons for Mexican defeat. There are some surprising omissions from the bibliography, such as James M. McCaffrey, Army of Manifest Destiny: The American Soldier in the Mexican War, 1846-1848 (1992) and Correspondence of James K. Polk (2004)). Nor does Murphy cite the War Department Letters Received from the National Archives. Yet he demonstrates a strong sense of the operational level of war, in explaining the plans, moves, and countermoves of both sides, and strong attention to intelligence and logistics (which have received little focused study for this conflict).
The greatest strength of Two Armies on the Rio Grande is that it is about both armies: Mexican leaders and forces get pretty much equal time, even though Murphy’s bibliography does not include any personal archival papers from Mexico. This attention is quite rare in most American scholarship on the war, particularly in books on battles and campaigns. How then does Murphy interpret the war, this campaign, and these battles?
Some historians have pictured the move toward war as inevitable given US expansionism, others as a plot planned by Polk. Murphy recognizes Polk’s strategy of provocation, but also that neither Zachary Taylor, the US commander in Texas, nor the Mexican commanders (Mariano Arista, Francisco Meíja, and Pedro de Ampudia) were eager for war. Instead, the dominant tone in Murphy’s narrative is one of uncertainty, friction, and internal divisions. The latter provides his principal explanation for Mexican defeat: that Mexican society and politics were too divided to provide the means to prepare effectively for war, and that Mexican commanders were unable to coordinate their efforts effectively. Social and political division is probably the most common scholarly interpretation for Mexican defeat, although the most recent synthesis, Peter Guardino’s The Dead March (2017), which gives more attention to Mexico than to the United States, attempts to replace it with the resource imbalance between the two nations. Murphy’s newest (“most original” doesn’t sound quite right) contribution is in exploring in depth Mexican military strategy and operations along the Rio Grande, emphasizing that Mexican commanders did choose when and where to initiate the first combat, and explaining their rationales. Yet it is not clear how this recognition of Mexico’s military agency changes the standard narrative of war causation, in which Mexican nationalism compelled a response to US provocations, enabling the United States to go beyond securing the Rio Grande border to declare war and invade New Mexico and (Alta) California.
What then is new in a highly detailed study that the author acknowledges follows beaten paths? First, Murphy connects Brian DeLay’s work on Indian raids into Mexico (War of a Thousand Deserts, 2008) to the dispersal of Mexican troop deployments, although he also observes, and explains in detail, the supply problems that might have prevented Mexico from concentrating a much larger force at Matamoros. Second, although he often questions Taylor’s understanding of artillery, he notes that Taylor’s troop training included exercises in combined arms tactics, which had been rare in the US Army before that date. Third, he shows the political, as well as the military and logistical, dilemmas that made Mexican leaders cautious even as US actions demanded response. Mexico’s president, Mariano Paredes, had been a military commander but restricted reinforcements to the Rio Grande during the autumn of 1845 as he plotted to overthrow the government. Once he did so, at the beginning of 1846, Paredes depended on the troops he had withheld from the north to maintain him in power in Mexico City, and so continued to withhold them from the likely theater of war. As a result, Paredes recognized the possibility of military defeat, and he feared that an early defeat would discourage any potential European assistance against the United States. Nevertheless, the caution this induced was undermined by the felt need to respond to the arrival of the US Army on the Rio Grande, in territory claimed by Mexico. Paredes was caught on the horns of a dilemma: he had to show his patriotism with a strong military stance against the United States, but was unwilling to send more troops.
Murphy finds that the Mexican army was not as large as has often been portrayed, but it still had an advantage of about three to two over the American (roughly 3,300 to 2,200—on such small forces did transformative events rest). Apart from American advantages in artillery, well known to both sides at the time, Murphy stresses divisions among the Mexican commanders. Indeed, he could do so even more, as one paragraph states that “Taylor had endured challenges to his leadership” (p. 157), which must mean criticism of his leadership, since there were no challenges. In other words, Murphy’s account of Taylor’s position in the army is a bit unclear. First he asserts that “Taylor’s junior officers regularly pointed out that ‘he knew little of tactics … and had not the confidence of the army like [Generals] Worth and Scott’” (p. 157), citing only an 1859 account by someone who had not been an officer. (Please, if you are writing about the nineteenth-century US Army officer corps, use the biographical dictionaries and Army Registers to see if someone you want to cite or quote was actually an officer.) Then Murphy observes that Taylor’s officers liked him, despite some private criticism. While Taylor was not the drillmaster Scott or Worth was, Scott was in Washington, and Worth never “challenged” Taylor’s command, which was clear by date of commission, date of rank, and date of brevet rank.
My apologies for that discursion; the US Army officer corps of that era is my specialty. Despite some confusing language, Murphy’s larger point is encapsulated as “Taylor had no real challengers for command of the army and faced none of the intrigue that ran rampant in the Mexican ranks” (p. 157). My first thought was, of course Taylor had no challengers: the US government made sure (and during that era always made sure) to make sure that it appointed a single commander, who was in command not only by appointment but by rank and seniority in that rank. (John C. Fremont did not understand this, but he was court-martialed and sentenced to dismissal from the army for his challenge to Stephen Watts Kearny, a sentence that James K. Polk confirmed. Edmund Gaines rushed into Florida early in 1836, and was rewarded by de facto exile to the Texas border, and never received another wartime command.) But my own reaction suggests just how much we take for granted, and how much difficulty Mexico was in when its commanders were scheming to usurp one another, indeed, to usurp the government itself.
These points aside, Murphy shows the growing cohesion of the US forces, in contrast to the Mexican ones. When it comes to the battles, he shows that the Mexican plan was confused: General Arista hoped to prevent the American infantry from exiting the chaparral, yet doing so limited the opportunity for his cavalry to act against those infantry. When battle came at Palo Alto, the American artillery dominated the field, firing about four times as many rounds as the Mexican artillery, decimating and demoralizing the Mexican infantry. The American infantry operated as “a well-oiled machine” (p. 205). The imbalance exacerbated the existing gap in cohesion, battlefield initiative and agility, and ultimately morale, giving the Mexican army little chance at Resaca de la Palma the next day, and little chance to hold Matamoros, in effect ending the campaign, or producing an operational pause as the Mexican army retreated to Monterrey and the American army rested and resupplied before advancing there late in the summer. Nor were Mexico’s troubles done: “The initial defeats … only sharpened divisions in [Mexico] and increased dissension” (p. 268).
What does all this mean historiographically? I reviewed Guardino’s The Dead March for the Journal of American History (December 2018) and questioned its thesis that disunity was less important to Mexican defeat than resource imbalance. This is a bit of a chicken-and-egg question, since each contributed to the other. Yet emphasizing resource imbalance implies an inevitable outcome, since that was not going to change in the two years between the US annexation of Texas and its seizure of Mexico City. Emphasizing Mexican disunity—which in political terms can be a critical position, rooted in the recognition that Mexico was run by creole elites at the expense of its mestizo or Indian peasants, rather than the assertion of Anglo chauvinism that some scholars seem to think—helps explain why Mexico fought despite this imbalance. Emphasizing disunity helps explain Mexican lack of resources (because of class-based political disputes over taxation and other means of revenue) and lack of military cohesion and soldier morale (because of conscription, because of leaders more concerned with their political futures than with those conscripts). And it helps explain the choices of Mexican commanders, connecting cause and effect more directly than lack of resources, which would have suggested making a deal with the United States to avoid greater losses, or withdrawing to Monterrey to gain greater access to supplies and compel the American army to extend itself.
It remains unclear whether Mexican commanders hoped that defeating the US Army on the Rio Grande would compel the United States to make peace, and certainly the resource imbalance enabled the United States to send another army if it wished—perhaps political division would have prevented the United States from doing so. But that would not have been the highly trained regular army that Taylor commanded. Here, too, Murphy’s book has the edge over Guardino’s as military history (Guardino has certainly written a remarkable social and cultural history): Guardino concentrates his examination of the US Army almost entirely on the volunteers, who were not present in this first campaign (and did not lead the advance or assaults on Mexico City). The resource disparity between the two nations only mattered if the United States chose to continue the war, which a defeat on the Rio Grande might have prevented. And despite the macroeconomic disparities, Winfield Scott’s army was outnumbered by more than Taylor’s had been, and was operating deep within Mexico, with guerrillas assailing his supply convoys from Veracruz. His artillery was better than the Mexican, but he had to assault fortified positions. Disparities in military proficiency, rooted in large part in disparities in military and national (social and political) cohesion, provide the most persuasive explanation for the outcomes of these battles and campaigns. Digging even deeper, the tragedy, a double tragedy, is that the United States had a herrenvolk (white man’s) democracy (or WMD, as I tell students) that provided its racially defined citizens with a base for that cohesion, while Mexico lacked any substantive democracy at all.
Samuel Watson is professor of US and military history at the United States Military Academy. His books Jackson's Sword: The Army Officer Corps on the American Frontier, 1810-1821 and Peacekeepers and Conquerors: The Army Officer Corps on the American Frontier, 1821-1846 (University Press of Kansas, 2012 and 2013) won the SMH Distinguished Book Award in 2014. He currently teaches electives on Cold War America and warfare between 1816 and 1918, and is editing the Oxford Handbook of American Military History. The views expressed in this review are those of the author and do not reflect the official policy or position of the Military Academy, the Department of the Army, DOD, or the US government.
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Citation:
Samuel Watson. Review of Murphy, Douglas A., Two Armies on the Rio Grande: The First Campaign of the US-Mexican War.
H-War, H-Net Reviews.
February, 2022.
URL: http://www.h-net.org/reviews/showrev.php?id=57067
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