The Convention of Aguascalientes
With Huerta gone, it was up to the victors to try and put Mexico back together. Obregón visited Pancho Villa on two occasions in August-September of 1914, but Villa caught the Sonoran scheming behind his back and held Obregón for a few days, threatening to execute him. He eventually let Obregón go, but the incident convinced Obregón that Villa was a loose cannon who needed to be eliminated. Obregón returned to Mexico City and renewed his alliance with Carranza.
On October 10, the victorious authors of the Revolution against Huerta met at the Convention of Aguascalientes. There were 57 generals and 95 officer in attendance. Villa, Carranza and Emiliano Zapata sent representatives, but Obregón came personally. The convention lasted about a month and was very chaotic. Carranza's representatives insisted on nothing less that absolute power for the bearded one and refused to budge. Zapata's people insisted the convention accept the Plan of Ayala. Villa's delegation was comprised of men whose personal goals were often conflicting, and although they were willing to compromise for peace, they reported that Villa would never accept Carranza as President.
Obregón was the big winner at the convention. As the only one of the “big four” to show up, he had the chance to meet the officers of his rivals. Many of these officers were impressed by the clever, self-effacing Sonoran and retained their positive image of him even when they fought him later. Some joined him immediately, including several important unaligned independents with smaller militias.
The big loser was Carranza, as the Convention eventually voted to remove him as First Chief of the Revolution. In the absence of Huerta, Carranza had been the de facto president of Mexico. The convention elected Eulalio Gutiérrez as President, who told Carranza to resign. Carranza hemmed and hawed for a few days before declaring that he would not. Gutiérrez declared him a rebel and placed Pancho Villa in charge of putting him down, a duty Villa was only too happy to perform. Obregón, who had gone to the Convention truly hoping for an end to the bloodshed and a compromise acceptable to everyone, was forced to choose between Carranza and Villa. He chose Carranza, and took many of the convention delegates with him.
Obregón vs. Villa
Carranza shrewdly sent Obregón after Villa. Obregón was not only his best general and the only one with any hope of taking down the powerful Villa, but also there was an outside chance that Obregón himself might fall to a stray bullet, which would remove one of Carranza's more formidable rivals for power.
In early 1915 Villa's forces, divided up under different generals, dominated the north. Felipe Angeles, Villa's best general, captured Monterrey in January, while Villa himself took the bulk of his forces to Guadalajara. In early April, Obregón, commanding the best of the federal forces, moved to meet Villa, digging in outside the town of Celaya.
Villa took the bait and attacked Obregón, who had dug trenches and placed machine guns. Villa responded with one of the old-fashioned cavalry charges which had won him so many battles early in the Revolution. Predictably, Obregón's machine guns, entrenched soldiers and barbed wire halted Villa's horsemen. The battle raged for two days before Villa was driven back. He attacked again a week later, and the results were even more devastating. In the end, Obregón completely routed Villa at the Battle of Celaya.
Giving chase, Obregón caught up to Villa once again at Trinidad. The Battle of Trinidad lasted 38 days and claimed thousands of lives on both sides. One additional casualty was Obregón's right arm, which was severed above the elbow by an artillery shell: surgeons barely managed to save his life. Trinidad was another huge victory for Obregón. Villa, his army in tatters, retreated to Sonora, where forces loyal to Carranza defeated him at the battle of Agua Prieta. By the end of 1915, Villa's once-proud Division of the North was in ruins. The soldiers has scattered, the generals had retired or defected, and Villa himself had gone back into the mountains with only a few hundred men.