Mexican citizen was most immediately affected by the Gadsden Purchase.
Explanation:
The treaty Gadsden purchase was signed in 1854 between Mexico and United States. Now Arizona is also a part of Mexico. But when the treaty was signed Arizona was not part of Mexico. The land area of Mexico was taken by United states and they had paid for that.
Though not all the members of United States government had supported The Gadsden purchase because they thought that newly occupied area by the United States would create problem in American civil war and it would be turned into slaves states.
