The right to keep and bear arms... but only sometimes.

Reason Magazine - Hit & Run > Are Guns on Campus Uniquely Dangerous?:

"As I said after the Virginia Tech murders, I am sympathetic to the idea that students and faculty members who are licensed to carry guns should be allowed to carry them on campus. "Gun-free zones" clearly do not protect people from gun-wielding maniacs (or ordinary criminals or scary ex-boyfriends) and may well attract them to places where they know their victims will be unarmed. Guns in the right hands can deter attacks or at least cut them short.

The downside of letting people carry weapons on campus is the same as the downside of letting them carry weapons anywhere else: Everyday arguments might escalate into deadly violence, accidents might happen, police (assuming they ever arrived in time) might mistake a law-abiding gun owner for an attacker, drunken gun owners could start whooping it up by wildly firing shots into the air, etc. These are the same arguments that gun controllers deployed in opposing the liberalization of concealed carry laws across the country, and the nightmare scenarios never materialized, even though 39 states now have nondiscretionary permit policies. On the whole, permit holders turned out to be remarkably well-behaved, committing crimes at a lower rate than the general population and rarely doing anything bad enough to lose their permits."