The current approach is inefficient and ineffective, imposing unnecessarily high costs due  (1) stranded capital investments from the installation of controls that later become obsolete when additional requirements are promulgated; (2) reduced lead time for complying with those requirements; (3) limited or non-existent flexibility for emissions trading to allow cost-efficient control options; and (4) a reliance upon lengthy, expensive, and uncertain litigation to sort out regulatory ambiguity and compliance with the law.