In 1853 Mexican president Santa Anna unintentionally ushered in a new era of liberal political consolidation and economic reform by triggering a backlash against his sale of territory along the northern border to the United States. In the Gadsden Purchase, Santa Anna sold Mexican land that U.S. engineers eyed as the route for a transcontinental railroad in exchange for $10 million that he mostly pocketed. Many Mexicans saw his act as a betrayal of the nation and threw their support behind a new generation of liberal leaders. Beginning with the presidency of Ignacio Comonfort (pres. 1855–1858), these liberals carried out sweeping legal and economic changes called La Reforma, or “the reform.”

Liberal reformers sought to make all individuals equal under the law and established property ownership as a basic right and national goal. The first major step in La Reforma was the Juárez Law (1855), which abolished old legal privileges for military officers and members of the clergy. The law was written by Minister of Justice Benito Juárez, an Indian from Oaxaca whose first language was Zapotec. Juárez began life as a farmer but earned a law degree and became the most important force in consolidating Mexico’s political system in the decades after independence. An even more consequential measure, the Lerdo Law (1856), banished another legacy of colonialism: “corporate lands,” meaning lands owned by groups or institutions, such as the Catholic Church, rather than by individual property owners. Since the beginning of the colonial era, the Catholic Church had been a major rural landowner, and liberals saw those landholdings as backward and inefficient. They wanted to redistribute church-owned lands among farmers who would own them as private parcels and who would profit from working them efficiently.

These liberal reforms triggered a backlash from conservative landowners and the church. When liberals enshrined these laws and other reforms in a new constitution ratified in 1857, the Catholic Church, which faced the loss of its lands as well as the loss of legal protections for the clergy, threatened to excommunicate anyone who swore allegiance to it. Conservatives revolted, triggering a civil war called the Wars of Reform (1857–1861). Liberal forces led by Benito Juárez defeated the conservatives, who then conspired with French emperor Napoleon III to invite a French invasion of Mexico. Napoleon III saw an opportunity to re-establish France’s American empire. His propaganda gave currency to the term “Latin America,” which the propagandists used to assert that France had a natural role to play in Mexico because of a common “Latin” origin.

The French army invaded Mexico in 1862. It faced little resistance other than the defense mounted by a young officer named Porfirio Díaz, who blocked the invaders’ advance through the city of Puebla on their way to Mexico City. The May 5 Battle of Puebla became enshrined as a national holiday (now also observed in the United States as “Cinco de Mayo”). Having expelled the Juárez government from Mexico City, Mexican conservatives and Napoleon III installed his Austrian cousin Maximilian of Habsburg as emperor of Mexico. In many respects, Maximilian was a good candidate for emperor: he was descended from Charles V, the Spanish emperor in whose name Cortés had conquered the Aztec Empire and claimed Mexico. He was politically able and quickly learned Spanish. But Mexico had been an independent nation for too long for a European power to install a foreign monarch.

The deposed Juárez led a guerrilla war against the French troops backing Maximilian. When the U.S. Civil War ended in 1865, the U.S. government sought to root out France’s influence on its border. The United States threw its support behind Juárez and pressured Napoleon III to remove French troops, and surplus Civil War armaments flooded across the border into Mexico. Juárez’s nationalists prevailed, restored Mexico’s republic, and executed Maximilian. Conservatives had been completely discredited: they had conspired with another country to install a foreign leader through a military invasion.

We can compare Benito Juárez, who governed the restored republic until 1876, with Abraham Lincoln. Both rose from humble rural origins to become able liberal lawyers. They both proved to be agile political and military leaders who prevailed in civil wars in which a liberal political philosophy triumphed over conservative opposition. The decade between the Wars of Reform that began in 1857 and Juárez’s restoration of the republic in 1867 can also be compared to the U.S. Civil War: both were watersheds in which questions of political philosophy and governing authority that had lingered since national independence were violently resolved.