What's so bad about unilateral action to protect the environment?

National actions to protect the environment can be more or less unilateral, ranging from those that promote purely national policies at one extreme to those that promote international norms at the other. Although the preference for international action to protect the environment is understandable, sometimes unilateral action can play a catalytic role in the development of an environmental regime. Moreover, often effective multilateral action is impossible, so the choice is not between unilateralism and multilateralism but between unilateralism and inaction. Rather than condemning unilateral action outright, we need to evaluate each particular unilateral action (or inaction) to determine whether it advances or detracts from desired ends.