Mexican Expedition

The **Mexican Expedition**, known in Mexico as the **Second Mexican-American War**, was an armed conflict between the United States of America and the Second Mexican Empire that lasted between January 3, 1919 and February 19, 1919. The conflict marked the first time since the Mexican-American War in the 19th century that the two states had gone to war and was a decisive victory for the American armed forces.

After a 1916 self coup saw Emperor Juan I of Mexico dismiss the democratically elected government and instal an autocratic loyalist regime, the governments of Mexico and the United States of America entered a phase of extreme tensions during the late 1910s as US president Woodrow Wilson sought to encourage the return of democracy in Mexico. In late 1918, the Mexican regime arrested the American ambassador Henry P. Fletcher on charges of 'inciting rebellion' and 'conspiracy against the government' - Fletcher would later die in a Mexican prison in November 1918, sparking domestic outrage in the United States.

In January 1919, the United States of America launched a military expedition into the Second Mexican Empire with the aim of capturing Mexico City and re-imposing democratic government. Under General John J. Pershing, the American forces were largely welcomed by the Mexican population and several Mexican state governments actively collaborated with the invading American forces. By contrast, the Imperial Mexican Army was led by prime minister General Manuel Plata and struggled to effectively deploy resources across the country - the Mexican forces also suffered from low morale and saw significant levels of defections.

After a month and a half of active combat, the Mexican government surrendered on February 19, 1919 after the American forces occupied Mexico City. Following the Mexican capitulation, General Pershing imposed a series of reforms on the Mexican government and forced Manuel Plata to resign as prime minister. A provisional transitional cabinet under Francisco Carvajal came to power in the aftermath and fresh elections were held in September 1919, which led to the formation of a progressive coalition government and the signing of an agreement to withdraw American soldiers from the country in February 1920. The final American soldier left the country in August 1920.

## Prelude

Following the 1910 death of the popular monarch Pedro II of Mexico, his significantly less popular successor Juan I engaged in a conflict with the democratically elected government of prime minister Francisco León de la Barra over the powers of the Mexican monarchy. In 1916, Juan I dismissed León de la Barra amid a constitutional crisis and appointed an autocratic loyalist government headed by Enrique Creel, and then later headed by General Manuel Plata.

In September 1918, the Mexican government arrested and imprisoned US ambassador Henry P. Fletcher on charges of 'inciting rebellion' and 'conspiracy against the government'. In November 1918, Fletcher died during his imprisonment, sparking widespread fury in the American press and inspiring calls for the US government to take action against the regime of Manuel Plata. On January 3, 1919, the United States Army launched an intervention into Mexico under the command of General John J. Pershing with the intent of taking punitive action against the Mexican government.

## Mexican Expedition

### American invasion of Mexico

Under the command of General John J. Pershing, the United States Mexican Corps launched their expedition into Mexico on January 3, 1919 by entering Nuevo Laredo city in Tamaulipas, before rapidly pushing south towards the city of Monterrey in Nuevo León after encountering little resistance from the regional garrison. Simultaneously, American border excursions took place across the entire northern border as America sought to create a buffer zone between its own cities and Mexico - only the state of Coahuila avoided US invasion, after state governor Eulalio Gutiérrez agreed to protect the border and aid the United States in toppling Manuel Plata's dictatorship and ending Emperor Juan I's authoritarian regime.

After prime minister Manuel Plata received news of the conflict on January 4, 1919, he ordered the full mobilisation of the Imperial Mexican Army against the American invading force and appointed himself as the commander of the defence forces, before travelling north with the army on January 8, 1919. The advance of the American armed forces was aided by several state governments, notably Coahuila and the State of San Luis Potosi, who gave the invading forces safe passage in exchange for allowing the governments to remain intact - the majority of these states were controlled by opposition parties that sought to depose Plata, although some were controlled by parties loyal to the federal government that simply wished to retain their own authority.

### Attempted Mexican assault

The two armies met for the first time at San Luis Potosi, where General Plata's Mexican army arrived on January 16, 1919 to discover that General Pershing held control of the city - subsequently, Manuel Plata attempted to retake the city using artillery to breach the historic city walls, but supply chain issues prevented his armoured divisions from functioning. As such, on January 19, 1919, Plata ordered a temporary retreat - however, the American forces followed the Mexican retreat and began to pursue the Mexican armed forces across the Mexican countryside, where sporadic battles were fought as the Mexican forces attempted to flee their pursuers. After briefly holding defence in the State of Hidalgo, Manuel Plata was ordered to return to Mexico City by Emperor Juan I on February 4, 1919.

### Surrender of the Mexican Empire

On February 10, 1919, General Manuel Plata and his forces returned to Mexico City, shortly followed by the American army on February 13, 1919. After briefly attempting to hold out a siege, Emperor Juan I formally issued a surrender on February 19, 1919 and invited the American forces into Mexico City, where they became the occupying force. Within days of the surrender, Manuel Plata resigned as prime minister of Mexico and was replaced by Francisco Carvajal, who was granted a temporary mandate to organise new fair elections. In September 1919, a general election was held in Mexico - the formerly governing Restoration Party saw a loss of more than 200 seats, whilst the opposition Mexican Radical Party and Progressive Party gained enough seats to form a coalition administration. On September 19, 1919, Pedro Lascuráin was appointed as prime minister of a US-allied coalition government.

## Peace Agreement

In the aftermath of their Mexican Expedition in January to February 1919, the United States of America formally occupied approximately 43% of Mexican territory and remained the dominant political and military power within the borders of Mexico by the time of Pedro Lascuráin's appointment as prime minister. As part of the Mexican Radical Party's manifesto for the 1919 general election, the party promised to sign a treaty with the US government within a year of coming to power in order to ensure the speedy removal of American soldiers from Mexican soil.

In October 1919, the coalition government passed the Negotiations and Sovereignty Restoration Act 1919 in order to enable the formation of a bi-partisan negotiation team led by foreign secretary Aureliano Urrutia and interior secretary Francisco Madero, with all political parties with more than forty eight seats (10% of the Congress of Mexico) able to send representatives to the delegation. On February 3, 1920, prime minister Pedro Lascuráin signed the Mexican-American Friendship Treaty alongside US general John J. Pershing at a ceremony in Mexico City - under the terms of the treaty, the United States pledged to withdraw all forces from Mexico within nine months in exchange for protection of American interests in Mexico and recognition of the American temporary occupation of the Mexican-American border (which bound by the treaty to end by 1930). Additionally, war reparations of $1 million USD were to be paid to the United States government before January 1, 1922 and the Mexican government was required to implement a new constitution within four years to officially limit the powers of the monarchy.