Calderon has greatly criticized the United States immigration system, stating that "unilateral measures" taken by the United States to enforce immigration laws have made "the persecution and humiliating treatment of undocumented Mexican workers worse." <ref>[http://jurist.law.pitt.edu/paperchase/2007/09/mexico-president-slams-us-immigration.php Mexico president slams US immigration rules]</ref> He is a strong opponent of a border fence and supports comprehensive immigration reform. Calderon believes that the United States has downplayed the positive effect that undocumented workers have contributed to the United States economy. <ref>[http://jurist.law.pitt.edu/paperchase/2007/09/mexico-president-slams-us-immigration.php Mexico president slams US immigration rules]</ref> <ref>[http://www.familysecuritymatters.org/homeland.php?id=811318%3Cbr+/%3E Now Official: Mexico Running US Immigration Policy by Sher Zieve]</ref> | Calderon has greatly criticized the United States immigration system, stating that "unilateral measures" taken by the United States to enforce immigration laws have made "the persecution and humiliating treatment of undocumented Mexican workers worse." <ref>[http://jurist.law.pitt.edu/paperchase/2007/09/mexico-president-slams-us-immigration.php Mexico president slams US immigration rules]</ref> He is a strong opponent of a border fence and supports comprehensive immigration reform. Calderon believes that the United States has downplayed the positive effect that undocumented workers have contributed to the United States economy. <ref>[http://jurist.law.pitt.edu/paperchase/2007/09/mexico-president-slams-us-immigration.php Mexico president slams US immigration rules]</ref> <ref>[http://www.familysecuritymatters.org/homeland.php?id=811318%3Cbr+/%3E Now Official: Mexico Running US Immigration Policy by Sher Zieve]</ref> |