"Prior to May 2011, Mexico's immigration policy was regulated by the highly strict General Law of Population of 1970, which had been portrayed in hypocritical light when compared to immigration policies as in the US states of Arizona or Alabama. However, on May 24, 2011, President Felipe Calderón signed the new and much more liberal Migration Law."

https://en.wikipedia.org/wiki/Illegal_immigration_to_Mexico#Migration_Law_of_2011