warfare, ensuring their grudging acquiescence to conservative Spanish rule until a less bloody path to independence could be found. It was at this juncture that the machinations of a conservative military caudillo coinciding with a successful liberal rebellion in Spain, made possible a radical realignment of the pro-independence forces.

Iturbide and the Plan of Iguala

In what was supposed to be the final government campaign against the insurgents, in December 1820, Viceroy Juan Ruiz de Apodaca sent a force led by a royalist criollo officer, Augustín de Iturbide, to defeat Guerrero's army in Oaxaca. Iturbide, a native of Valladolid, had gained renown for the zeal with which he persecuted Hidalgo's and Morelos's rebels during the early independence struggle. A favorite of the Mexican church hierarchy, Iturbide was the personification of conservative criollo values, devoutly religious, and committed to the defense of property rights and social privileges; he was also disgruntled at his lack of promotion and wealth.

Iturbide's assignment to the Oaxaca expedition coincided with a successful military coup in Spain against the new monarchy of Ferdinand VII. The coup leaders, who had been assembled as an expeditionary force to suppress the American independence movements, compelled a reluctant Ferdinand to sign the liberal Spanish constitution of 1812. When news of the liberal charter reached Mexico, Iturbide saw in it both a threat to the status quo and an opportunity for the criollos to gain control of Mexico. Ironically, independence was finally achieved when conservative forces in the colonies chose to rise up against a temporarily liberal regime in the mother country. After an initial clash with Guerrero's forces, Iturbide switched allegiances and invited the rebel leader to meet and discuss principles of a renewed independence struggle.

While stationed in the town of Iguala, Iturbide proclaimed three principles, or "guarantees," for Mexican independence from Spain: Mexico would be an independent monarchy governed by a transplanted King Ferdinand or some other conservative European prince, criollos and peninsulares would henceforth enjoy equal rights and privileges, and the Roman Catholic Church would retain its privileges and religious monopoly. After convincing his troops to accept the principles, which were promulgated on February 24, 1821, as the Plan of Iguala, Iturbide persuaded Guerrero to join his forces in support of the new conservative manifestation of the independence movement. A new army, the Army of the Three Guarantees, was then placed under Iturbide's command to enforce the Plan of Iguala. The plan was so broadly based that it pleased both patriots and loyalists. The goal of independence and the protection of Roman Catholicism brought together all factions.

Rebel forces from all over Mexico joined Iturbide’s army. When the rebels' victory became certain, the viceroy resigned. On September 27, 1821, representatives of the Spanish crown and Iturbide signed the Treaty of Córdoba, which recognized Mexican independence under the terms of the Plan of Iguala. Iturbide, a former royalist who had become the paladin for Mexican independence, included a special clause in the treaty that left open the possibility for a criollo monarch to be appointed by a Mexican congress if no suitable member of the European royalty would accept the Mexican crown.