North American oil markets are entering a new an era of insecurity in market access, with major implications for economic, environmental and energy policy. For the past 35-40 years, the insecurities around oil were concerned with its supply, not with market access. That reality drove investments in the development of energy technologies and the protection, by military and political means, of access to oil resources in the Middle East. However, over the past few years, four forces – supply, competition, demand and social license – have been working in concert to propel North America into a new era in which economic, environmental and energy policy will be defined by insecurity in market access. This article explores these forces with a particular focus on the crude oil transportation bottleneck that has developed across United States and Canada.