<P> The federal assault weapons ban was never directly challenged under the Second Amendment . Since its expiration in 2004 there has been debate on how it would fare in light of cases decided in following years, especially District of Columbia v. Heller (2008). </P> <P> A 2002 study by Koper and Roth found that around the time when the ban became law, assault weapon prices increased significantly, but this increase was reversed in the several months afterward due to a surge in assault weapons production that occurred just before the ban took effect . </P> <P> In 2003, the Task Force on Community Preventive Services, an independent, non-federal task force, examined an assortment of firearms laws, including the AWB, and found "insufficient evidence to determine the effectiveness of any of the firearms laws reviewed for preventing violence". A 2004 critical review of firearms research by a National Research Council committee said that an academic study of the assault weapon ban "did not reveal any clear impacts on gun violence outcomes". The committee noted that the study's authors said the guns were used criminally with relative rarity before the ban and that its maximum potential effect on gun violence outcomes would be very small . </P> <P> In 2004, a research report commissioned by the National Institute of Justice found that should the ban be renewed, its effects on gun violence would likely be small, and perhaps too small for reliable measurement, because rifles in general, including rifles referred to as "assault rifles" or "assault weapons", are rarely used in gun crimes . That study by Christopher S. Koper, Daniel J. Woods, and Jeffrey A. Roth of the Jerry Lee Center of Criminology, University of Pennsylvania found no statistically significant evidence that either the assault weapons ban or the ban on magazines holding more than 10 rounds had reduced gun murders . The authors also report that "there has been no discernible reduction in the lethality and injuriousness of gun violence, based on indicators like the percentage of gun crimes resulting in death or the share of gunfire incidents resulting in injury ." </P>

Who allowed the assault weapons ban to expire