Using the example of environmental management systems (EMS) and the ISO 14001 standard, I propose a typology of eight ways in which public authorities interact with voluntary environmental initiatives: 1. Steering (influencing the development, use or content of voluntary initiatives through official policy pronouncements, participation in standards development or creation of legal ground rules or backstops for voluntary initiatives), 2. Self-discipline (applying voluntary initiatives to government operations or agreeing to international trade rules that turn voluntary standards into constraints on regulatory authority), 3. Knowledge production (generating and disseminating ideas, information and expertise about the design, use or value of voluntary initiatives), 4. Reward (providing material incentives for adherence to voluntary initiatives through regulatory relief programs, financial incentives or green procurement policies), 5. Command (issuing legally binding requirements to adhere to voluntary initiatives through court orders or legislation), 6. Benchmarking (using voluntary initiatives as standards for "reasonableness" in civil actions or "due diligence" in regulatory prosecutions), 7. Challenge (challenging firms or other organizations to adhere to voluntary initiatives), and 8. Borrowing (incorporating voluntary initiatives into legal instruments such as statutes and regulations). I then employs Foucault's notion of governmentality to characterize EMSs and EMS standards as a mode of governance with their own normative rationales and mundane technologies of rule. I argue in this connection that the techniques of EMSs and standardization deactivate the substantial political stakes of corporate environmental management by treating them as technical matters to be resolved by neutral professional expertise and simultaneously as private matters of consumer or commercial preference to be resolved by the market. The political rationalities of EMSs and EMS standards consist of a particular set of justifications and story-lines that vest the development and implementation of important environmental standards in global standardization bodies, business firms, consultancies and private certification and accreditation bodies. This analysis of the governmental rationalities and techniques of EMSs and the interpenetration of public and private authority in the politics of environmental management casts new light on the debate over what role EMSs should play in public law and policy. I conclude the article with some tentative thoughts on what role law might play in this arena -- in particular, how it might be employed to resist the tendency of EMS-based initiatives to depoliticize environmental politics.