If a prime goal of energy policy is to achieve energy security, why is there a controversy over the proposed Keystone XL pipeline, designed to deliver new supplies of oil from within North America? This Viewpoint seeks answers in the debate over the underlying purposes of energy policy: how does one answers the question "what do we want from energy policy?" Perceptions of feasible answers and policy options change over time, as witnessed in the 1970s. Analogous shifts in opinion are changing today's policy debates and widening the contradictions in policy purposes. Attention to the existence of these contradictions, without illusions, is necessary to meet the policy challenges of the future effectively. (c) 2013 Elsevier Ltd. All rights reserved.