Comment by National Governors Association

State laws may be preempted only by an Act of Congress. Congress should preempt state laws only to the extent necessary to achieve a clearly stated national objective and, when doing so, federal legislation should: * accommodate state actions taken before its enactment, where possible; * permit States that have developed stricter standards to continue to enforce them; * permit States that have developed similar standards to continue to adhere to them; and * permit States to enforce any national standards enacted.