From the Introduction: "Criminal activity along the Southwest Border (SWB) poses a significant national security threat to the United States. The almost 2,000-mile border that separates the United States and Mexico includes major population centers, transportation hubs, Tribal lands and Tribal Trust lands, and large tracts of uninhabited desert. Mexican Transnational Criminal Organizations (TCOs) are the greatest drug trafficking threat to the United States; they control most of the U.S. drug market and have established varied transportation routes, have advanced communications capabilities, and hold strong affiliations with criminal groups and gangs in the United States. Mexican TCOs supply the majority of the heroin, fentanyl, methamphetamine, cocaine, and foreign-produced marijuana available in U.S. illicit drug markets. These drugs are also smuggled into the United States across other land, sea, and air borders, but not on the same scale as the substances transported across the SWB."
White House: https://www.whitehouse.gov/