As more attention and resources are poured into the U.S.-Mexico border, U.S. Border Patrol agents along the northern border have struggled with limited resources and manpower; the nearly 4,000 mile U.S.-Canada border is roughly twice as long as the southern border, yet there are only 2,200 agents posted along it compared to 18,000 agents in the south; Border Patrol agents in the north say they lack the resources to do the job; smuggling rings, especially drug traffickers, exploit the gaps in security along the northern border to ship large quantities of drugs to the United States