In recent years, the notion of a nexus involving water, energy, and food has been gaining attention in the scholarly literature and popular press, due partly to the impetus provided by an international conference on the nexus in 2011, and partly to the increasing interest among researchers and public officials in determining the investments and policies needed to achieve and sustain water, energy, and food security. While the notion of such a nexus is compelling to some observers, interactions involving water, energy, and food have been known and studied for many years by scientists and policy analysts. The need for greater integration of research and policy discourse across sectors and regions has been expressed in international meetings since the late 1940s. In addition, the conceptual basis for including water, energy, and food in the “nexus,” to the exclusion of other resources and inputs is not evident. In many cases, the information excluded from studies claiming to implement a nexus approach might be of greater importance to science and policy than the information included in the analysis. In this paper, I review some of the experience gained in earlier attempts to enhance integration and policy coherence, and to promote systems analysis. The challenges observed in implementing programs of integrated natural resources management (INRM) and integrated water resources management (IWRM), in particular, suggest that efforts to implement a water-energy-food nexus approach will not enhance the policy process in all settings. In sum, it is not clear that the increasing attention given to studies claiming to implement a nexus approach is warranted.