The Canada-US border, like all international borders, performs certain functions related to restricting, regulating and interdicting cross-border flows of people, products and pollutants. How border officials carry out these functions is shaped by historical factors and the political-economic agendas of state authorities. Though Canada-US border management has always been influenced by security issues such as boundary disputes, prohibition and illicit drugs, only since 9/11 has the border been viewed as a vital security problem in the context of American national security. This new reality has brought increased attention to the northern border and prompted a continuing debate about the appropriate balance between securitization of the border and facilitation of trade and social interaction.
Alper, Donald and Hammond, Bryant, "Stakeholder Views on Improving Border Management" (2009). Border Policy Research Institute Publications. 81.