Almost all U.S. college campuses ban concealed weapons. But in the aftermath of the tragic shooting deaths at Virginia Tech in 2007, the debate on whether guns should be permitted at colleges and universities has intensified. Dozens of states have considered proposals to lift bans on concealed weapons at colleges and universities, but so far none have been successful. While there is no research on the effect of allowing guns at colleges and universities when it comes to shooting violence, according to "Violence Prevention: The Evidence" (World Health Organization, 2009) "jurisdictions with restrictive firearms legislation and lower firearms ownership tend to have lower levels of gun violence. Measures include bans, licensing schemes, minimum ages for buyers, background checks and safe storage requirements." Students for Concealed Carry on Campus and other right-to-carry activists argue that college campuses would be safer if students and other private citizens (faculty, staff, and visitors) were allowed to carry concealed weapons in order to protect themselves. However, a growing body of evidence shows that concealed carry permit holders are a threat to public safety. The American Association of State Colleges and Universities and more than 90 colleges and universities from 24 states have signed a resolution by the Campaign to Keep Guns Off Campus that they are opposed to legislation that would mandate that colleges and universities allow students to carry concealed weapons on campus. According to the association, 23 states currently allow public campuses or state systems to decide their own weapons policies, with nearly all choosing to be "gun-free" ("The Denver Post," Dec. 2, 2009).