All of Mexico Movement facts for kids

The All of Mexico Movement was a political idea in the United States during the Mexican–American War (1846–1848). It was a plan to make all of Mexico part of the United States. This idea was part of a bigger belief called Manifest Destiny, which suggested that the U.S. was meant to expand across North America. However, the All of Mexico Movement never actually happened.

The Mexican-American War led to the U.S. taking control of California and other areas in northern Mexico. American soldiers also went into the more populated central parts of Mexico. After the U.S. Army captured Mexico City, some people became very excited about the idea of adding all of Mexico to the U.S. But this idea faced strong opposition in the U.S. Congress, especially from Senator John C. Calhoun of South Carolina. He was against adding land with many non-white people.

The Treaty of Guadalupe Hidalgo officially ended the war and also ended the hopes of the All of Mexico Movement. This treaty gave the U.S. the less populated northern parts of Mexico, but not the entire country.

Why it Started

Before James K. Polk became U.S. President in 1845, the U.S. Congress approved the idea of adding Texas to the United States. Texas had declared its independence from Mexico in 1836, but Mexico still claimed it. This disagreement helped start the Mexican–American War on April 24, 1846.

By the summer of 1847, the U.S. was winning many battles. This success made some people, especially Democrats in the eastern U.S., call for taking all of Mexico. They believed that bringing Mexico into the U.S. would help keep peace in the region.

Why People Opposed It

The idea of taking all of Mexico was very controversial. Some people who believed in Manifest Destiny, like John L. O'Sullivan, had always said that U.S. laws should not be forced on people who didn't want them. Taking all of Mexico would go against this idea. It would also mean making millions of Mexicans U.S. citizens, which was a big debate.

This discussion highlighted a problem within the idea of Manifest Destiny. Some people believed that Mexicans, because they were not white, were not suitable to become U.S. citizens. However, another part of Manifest Destiny suggested that Mexicans would improve by becoming part of American democracy. So, while some ideas within Manifest Destiny pushed for expansion, other ideas within it were used to argue against taking all of Mexico.

Many Americans were also worried about Mexico's Catholicism, its weaker form of republicanism, and the possibility of a rise in Mexican nationalism if they were annexed.

Why it Failed

The debate about taking all of Mexico eventually ended with the Mexican Cession. This agreement added the territories of Alta California and Nuevo México to the United States. These areas were much less populated than the rest of Mexico. Like a similar movement to take all of Oregon, the All of Mexico Movement quickly faded away.

Historian Frederick Merk wrote in his 1963 book, Manifest Destiny and Mission in American History, that the failure of both the All of Oregon and All of Mexico movements showed that Manifest Destiny might not have been as popular as many historians thought. Merk believed that the idea of spreading democracy was important in American history. However, he argued that aggressive expansion, or "continentalism," was supported by only a few Americans, mostly Democrats, and was opposed by others, including some Democrats and most Whigs.

Images for kids

• 

  This painting by Carl Nebel shows Winfield Scott entering the main square in Mexico City, the Plaza de la Constitución. The Metropolitan Cathedral is in the background.