"...march from Santa Ana towards Guatemala City was predicated on the Nicaraguan National Guard that Butler had spent the last two years building into a formidable fighting force would be enough to keep the threat against forces in eastern Honduras real enough to prevent them from attacking through his rear, and that the newly-formed Isthmian Expeditionary Force of thirty thousand men from the Army meant to serve as auxiliaries alongside the Marines thrusting into the heart of Centro would be sufficient support. The reality of the campaign of summer 1915 was that many of its predicates were woefully wrong; the IEF had, unlike Butler's rugged "Jungle Jims," not been exposed to the kind of brutal, humid and malarial fighting conditions in the sweaty, forested hills of the Isthmus that had gotten the core of the Marines in El Salvador experienced in the type of war they were fighting. Yellow fever and other diseases ripped through the Army men, slowing Butler's march as much as frequent guerilla attacks and the extremely difficult terrain between Santa Ana and the capital, where a single narrow road looped through high mountains and thick foliage, and retreating Centro forces alternated between staging ambushes from the trees or burning the jungle so that it was so thick with smoke Butler's men could not advance. The Nicaraguans, meanwhile, bent but did not break, relinquishing a fair deal of land to Centroamerican-Mexican forces to the point they had to withdraw south of Esteli, but this fighting retreat into the teeth of American defenses set up in Nicaragua did pull that weight of forces away from Butler's columns.
This was the context in which the events of August 2nd, 1915 occurred. The Americans were winning, but they were winning slowly and brutally and at great cost. The Centroamericans were collapsing, but not so quickly that it threatened Mexican positions, with the road network in Honduras essentially still intact for Huerta's men to move via Tegucigalpa, the place he had initially expected Butler to strike towards. Resupply for the Bloc by sea was impossible, and Mexican soldiers were getting increasingly hungry, antsy and frustrated, with fights frequently breaking out between Centroamerican recruits and Huerta' more professional men, who pejoratively called their allies monos - monkeys. Huerta, no stranger to ambition and ruthlessness in his rise in the ranks of the Mexican Army, finally had had enough. After two years of war, Estrada Cabrera had done nothing but complain about Nicaragua daring to exist and indulged corruption and incompetence within his own ranks as Mexico bled in the Isthmian jungles to defend him. Above and beyond that, it was not an uncommon view in Mexican circles that Centroamerica existed in the first place at Mexico's pleasure, as it had been the unequivocal support of the Emperor Maximilian in the 1870s and early 1880s for Justo Rufino Barrios' project of uniting Guatemala, El Salvador, and Honduras into a single state that had seen the federation come about. To put the overriding Mexican attitude into American colloquial terms, it was Mexico that had brought Centro into the world, and thus Mexico who could take it out.
Early on the morning of August 2nd, 1915, the ostentatious Presidential Palace in Guatemala City was attacked - not by American Marines, who were about sixty-five kilometers away, but by elite Mexican forces personally loyal to Huerta. Surprised, the Centroamerican guards were rapidly overwhelmed and killed to the man. Soon afterwards, President Manuel Estrada Cabrera, one of the bete noires of the United States in the first decade and a half of the 20th century for his indulgence of Confederate and Mexican meddling with American businesses in Centroamerica and his belligerency towards Nicaragua, was dragged out into the courtyard, placed up against a wall, and executed not to the calm intonations of his last rites but over his livid screams and protests.
Huerta's decision to simply usurp command over Centroamerica remains controversial even in Mexico, where he is pilloried for the decision. An exploration of his thinking is meant not to absolve him of his unilateral murder of his ally Estrada Cabrera but rather to understand the context of the events of August 2nd. In the view of Huerta and his staff, who were returning to Guatemala City later that day to secure order after the city plunged into chaos, Centroamerica was effectively done the moment El Salvador fell earlier in the year, and they were highly dubious of the ability of Estrada Cabrera's men to defend Guatemala City. Rather than throw more blood and treasure into the matter, they instead proposed the dissolution of the Union, letting Honduras fend for itself, and throw all Mexican attention towards preserving their position in Guatemala, which had always been the main focus of Mexico City anyhow.
To say that this decision was unpopular in Mexico City would be an understatement, especially as Huerta reorganized the Centroamerican government by force into the "Military District of Guatemala" with himself as its Supreme Commander, viewed on both sides of the border as a prelude to him simply declaring himself as Guatemala's warlord. General Bernardo Reyes, the Chief of Staff of the Mexican Army, issued a warrant for his arrest and court martial, and twenty thousand Mexican soldiers were diverted from marching north to Los Pasos to instead be sent to Guatemala to secure the territory, auguring a potential battle between rival Mexican factions. This debacle was a further sign to Mexico's internal opponents of continuing the war, of whom Reyes was an increasingly important voice, that continuing on the current course would lead to ruin for Mexico and that it was best to simply cut losses and agree to a separate peace with the United States while there was a good deal to be had rather than continue down the sinking ship with the Confederacy and, apparently, Centroamerica, which over the course of August was pulverizing itself back into three separate nation states before Mexico's very eyes, with anti-Huerta riots, mutinies and declarations spreading across Honduras and northern Guatemala with remarkable speed..."
- The Forgotten Front: The Isthmian Campaigns of the Great American War
