As our nation made great efforts during 2002 to respond to the events of September 11, 2001, the focus of our relationship with Mexico went through dramatic changes. Needless to say, these changes were felt all along the 2,000-mile border between the two countries and throughout tribal communities within the region. Homeland security and immigration control were necessary components of the Administrations strategy for reducing the risk of terrorists using the border region to infiltrate or harm the United States. Pre-September 11, we were close to reaching mutual understandings on migration, trucking and security cooperation, which would have had an impact on our environmental dialogue with Mexico. Given that many of our trans-boundary environmental problems along the U.S.-Mexico border can be linked to inadequate border cooperation, the understandable attention to these other developments meant less focus on environmental cooperation. Longer wait times for vehicles at the border, increasing populations, and extensive agricultural water use all exacerbated an already complicated relationship.