Abstract: Environmental law and energy law, two historically disparate fields, seem to be converging. Energy regulation has begun to seriously address environmental concerns for the first time, and environmental law is increasingly becoming a driver of energy policy. This Article describes the legal mechanisms through which greater congruence has been achieved, while acknowledging the still significant and stubborn barriers to true integration, which likely will be difficult to overcome. It shows that federal agencies have taken steps toward greater policy alignment by repurposing existing statutory provisions and relying on previously under-utilized legal authorities for the first time, in a carefully calibrated process of legal innovation. Yet it also shows this process to be meaningfully constrained by the agencies' adherence to their own distinct missions, and by the constraints of their particular statutory authorities. The Article builds on the work of scholars who have lamented the divide between energy and environmental law, and urged that it be dismantled. Most of the accounts to date suggest that environmental rules and energy sector regulation, which are so obviously interrelated, inevitably will be drawn closer together. The analysis here looks more closely at the drivers of convergence to date, and presents a more nuanced picture of events. The trend toward greater policy alignment, while real, is limited. Energy and environmental regulators have not embraced convergence as an independent goal, but rather have achieved it incrementally and indirectly, as a consequence of pursuing their traditional missions during a time of change. These agencies have reacted to numerous external forces--technological innovation, market shifts, scientific developments, federal and state regulatory measures--which have prompted them to respond with their own initiatives. Yet they remain constrained by the bounds of their governing statutes and the confines of their long established regulatory roles. Tellingly, these agencies have tended to justify their policy innovations as necessary to fulfill their own traditional mandates, not to help other agencies realize theirs. The Article ultimately concludes that claims of convergence between the two fields should be tempered. However desirable greater policy congruence might be, it has not been mandated by Congress, explicitly commanded by the President, or centrally directed by anyone else. And it is not inevitable. The most that can be said is that convenient alignments may arise when the imperatives of these different regulators coincide. Thus, the story of “convergence” between energy and environmental goals is one of gradual steps rather than great leaps--of interest-based compatibility rather than love-struck merger.