"Historically, national borders have evolved in ways that serve the interests of central states in security and the regulation of trade. This book explores the Canada and US border and security policies that have evolved from successive trade agreements since the 1950s, punctuated by new and emerging challenges to security in the twenty-first century. The sectoral and geographical diversity of crossborder interdependence of what remains the world's largest bilateral trade relationship makes the US and Canada border a living laboratory for studying the interaction of trade, security, and other border policies that challenge traditional centralized approaches to national security. The book's findings show that border governance straddles multiple regional, sectoral, and security scales in ways rarely documented in such detail. These developments have precipitated an Open Border Paradox: extensive, regionally varied flows of trade and people have resulted in a series of nested but interdependent security regimes that function on different scales and vary across economic and policy sectors. These realities have given rise to regional and sectoral specialization in related security regimes. For instance, just-in-time automotive production in the Great Lakes region varies considerably from the governance of maritime and intermodal trade (and port systems) on the Atlantic and Pacific coasts, which in turn is quite different from commodity-based systems that manage diverse agricultural and food trade in the Canadian Prairies and U.S. Great Plains"-- Provided by publisher.