This thesis explores the different perspectives that the Clinton, Bush, and Obama administrations have had towards illegal immigration and border enforcement on the U.S.-Mexico border. Subsequently, it also explores what policies and laws that have been enacted. Historically, the U.S. has been quite open to immigration from Mexico. Especially since the end of the Bracero program, illegal immigration from Mexico has been a recurrent problem that at times has resulted in strict policies imposed by the U.S. government. During the last twenty years, this problem has become more profound and a visible escalation of border enforcement has occurred. The three administrations have in many ways employed three different strategies to deal with the issue. The Clinton administration was faced with the challenge of strengthening the border at the same time that it wanted to keep it open to trade. However, the Clinton administration started the build-up that escalated out of proportions after the attacks on September 11. As a response to this, the Bush administration resorted to a legislative approach that subsequently has resulted in a more militarized border in the name of national security. During the Obama administration, the U.S. has experienced a standstill in illegal immigration from Mexico. However, the administration has concentrated their efforts on interior enforcement and is now pushing for immigration reform. Despite these differences, one can also see a continuation of policies that can be traced from the onset of Operation Gatekeeper until today.