On November 14, 1997, the President and the Secretary of the Treasury ordered a review of the importation of certain modified versions of semiautomatic assault rifles into the United States.1 The decision to conduct this review stemmed in part from concerns expressed by members of Congress and others that the rifles being imported were essentially the same as semiautomatic assault rifles previously determined to be nonimportable in a 1989 decision by the Bureau of Alcohol, Tobacco and Firearms (ATF). The decision also stemmed from the fact that nearly 10 years had passed since the last comprehensive review of the importation of rifles, and many new rifles had been developed during this time.