The All of Mexico Movement, or All Mexico Movement, was a political movement to expand the United States to incorporate all of Mexico.[1] It was a controversial aspect of Manifest Destiny that was unable to garner enough political support to encourage adoption. The Mexican-American War (1846–1848) brought the United States and Mexico into conflict over various geopolitical issues, including a desire to invade and annex much of Mexico, that resulted in victory for the United States.
After the US Army took Mexico City, there was renewed enthusiasm for incorporating all of Mexico. There was fierce opposition to the idea within the U.S. Congress over various internal political disputes. The US army found themselves in the midst of guerilla warfare in Tamaulipas, between Veracruz and Mexico City, making it impossible for America to take any effective control of Mexico, while simultaneously losing men, supplies and military equipment. While the American forces in Tamaulipas tried to subjugate the local population through violence and terror, in Mexico City and Veracruz, they tried to respect and not interfere with the local population. Both approaches failed, and it was only due to this increase in violence and insurrection that Mexican leaders saw the necessity of establishing a peace with the US. Similarly, it was urgent for the US to end the conflict and maximize territorial gains while minimizing unneeded losses.