Good governance is essential for achieving ecologically sustainable development. Sustainable development includes a cluster of principles, including the precautionary principle. All branches of government play a role in ensuring good governance, both individually and synergistically. The judiciary has an important role in promoting ecologically sustainable development, especially through the implementation of the precautionary principle in environmental cases. However, their capacity tends to be under-appreciated, partly due to an unjustified focus on the political aspects of government but also because of institutional factors that impede the judiciary in fully performing its role and hence in promoting and implementing the precautionary principle (along with other aspects of good governance). This chapter examines these impediments. Focusing particularly on the Australian state of New South Wales, home to a specialist Land and Environment Court, we use a systems approach to identify the factors that impede the effectiveness of the court in implementing the precautionary principle for environmental protection. We consider what the court might do to improve effectiveness, including mechanisms involving the executive and judicial fields of activity, institutional reform and integration of ideas. Despite increasingly sophisticated governance arrangements, Australia’s natural environment continues to deteriorate, a problem that is not unique to Australia. The failures of implementation of legal governance have been highlighted in the Rio+20 communique, by the IUCN and by the Chief of Staff of the Secretary General of the Organization of American States, who has referred to the implementation of international environmental agreements as ‘the greatest challenge of our century’. Scholars’ and citizens’ expectations that the judiciary can ensure the proper implementation of environmental laws may not always be realistic. In this chapter, we explore systemic factors that constrain the judiciary of a state or nation in ensuring the implementation of environmental laws (which may be based in international environmental agreements or rules), and suggest directions to optimize this role.