The best single way

"The single best way to respond to a mass shooter is with an immediate, violent response. The vast majority of the time, as soon as a mass shooter meets serious resistance, it bursts their fantasy world bubble. Then they kill themselves or surrender. This has happened over and over again."
http://larrycorreia.wordpress.com/2012/12/20/an-opinion-on-gun-control/

via Instapundit