After the fall of Huerta, while still under the command of Sánchez, he briefly supported the conventionalist government of Eulalio Gutiérrez, before breaking with Sánchez to ally with the constitutionalist army of Venustiano Carranza. Shortly after Sánchez and Amaro joined the Constitutionalists, Sánchez ordered Amaro to attack a column of troops commanded by General Francisco Murguía, who, while also a Constitutionalists, was a rival of Sánchez. While initially successful, Murguía's troops eventually prevailed, and Murguía sought to have Amaro executed for treason, a charge he narrowly escaped. Rather than damaging the reputation of Amaro, however, the incident did more to isolate Sánchez, who Amaro abandoned. The split finally came in 1915, when Amaro advanced the troops under his command on the Villista "División del Norte", leaving Sánchez in Michoacán. By this time, he had already professed allegiance to General Álvaro Obregón and the carrancista government.