Gadsden Purchase
A treaty was signed on December 30, 1853. This treaty would have given  to the United States and 15,000,000 dollars to Mexico. Many US Senators did not agree with this: they wanted to buy less land. On April 25, 1854, the US Senate accepted the new, smaller purchase. President Franklin Pierce signed the treaty, and then sent it to President Santa Anna, who signed it on June 8, 1854. Many Mexicans were angry with Santa Anna after he signed the treaty.