 The United States Department of Homeland Security has also said that it is considering using state National Guard troops to help the U.S. Border Patrol counter the threat of drug violence in Mexico from spilling over the border into the U.S.The governors of Arizona and Texas have encouraged the federal government to use additional National Guard troops from their states to help those already there supporting state law enforcement efforts against drug trafficking.According to the National Drug Intelligence Center, Mexican cartels are the predominant smugglers and wholesale distributors of South American cocaine and Mexico-produced cannabis, methamphetamine and heroin.