The fuel for dynamic change in the United State’s energy relationship with Canada lies in immense deposits of tar sands beneath the boreal forests of Alberta province. Unconventional production of oil from this resource has accelerated in recent years and remains poised for continued expansion, facilitated, in part, by plans to import tar sands crude through new pipelines to refineries in the United States. However, the development of this resource carries uniquely heavy environmental burdens, and U.S. environmental groups have challenged the process by which the United States authorizes cross-border oil pipelines. This thesis analyzes the presidential permitting process and concludes that executive or legislative action is necessary to eliminate legal uncertainties and improve the transparency and public acceptability of determinations that new cross-border pipelines are warranted. / text