 Complete the following phrase:  Gun control advocates and gun rights advocates have referred to at least some of the features outlined in the federal Assault Weapon Ban of 1994 as cosmetic. The NRA Institute for Legislative Action and the Violence Policy Center both used the term in publications that were released by them in September 2004, when the ban expired. In May 2012, the Law Center to Prevent Gun Violence said that the inclusion in the list of features that were purely cosmetic in nature created a loophole that allowed manufacturers to successfully circumvent the law by making minor modifications to the weapons they already produced. The term was repeated in several stories after the 2012 Aurora, Colorado shooting and the Sandy Hook Elementary School shooting. Senator Marco Rubio cited that issue during a town hall forum, responding to questions from survivors of the 2018 