Suggested reading before this: The Mexican War
The Mexican war had exhausted Mexico's economy, and there was political confusion brewing. Santa Anna had again had seized power in 1853, and ruled as a dictator. But the liberals had been gaining confidence, and power, since the war. In 1855, they drove Santa Anna out of power.
Inspired by the liberal political philosophies of European men such as: Jean-Jacques Rousseau, John Stuart Mill, and Pierre Joseph Proudhon;
Benito Juarez, and other men gave the movement for the liberals effective leadership, the liberals promised a better overall life, and promoted the ownership of private land. The reform was advertised to be the equivalent of the French Revolution. Several laws were made, known as the Reform Laws. These laws reaffirmed the a elmination of slavery, and guaranteed civil rights for all Mexicans.
However, the reform and the constitution, which both shared a more liberal view, seperated the political classes and set the stage for the Mexican Civil War. The conservatives, launched a plan called "Tacubaya", and, with the support of the military and clergy, arrested Juarez. Juarez escaped however, and created a "Government in Exile". The conservatives held the main military advantage, being that they were better equipped and had more supply. But in 1860, the situation had changed, the final battle took place just before Christmas. The winning liberal army, marched into Mexico City on January 1st, and was soon elected president in March of 1861.
Despite winning the war, Mexico was in even more of a debt crisis than before, one of the first things Juarez did, was suspend payment on the loans, to the european powers. This would be the reason for one of the biggest wars in history, which had a famous battle: Cinco De Mayo