The Columbine Massacure was facilitated by the lack of gun rights. Schools are no-gun zones. Would you feel safe with a no-gun zone sign on your front lawn? 

 No one at Columbine was armed; except of course the two boys. Since they had a monopoly of firepower they could walk around killing whomever they wanted. Now, if the teachers and/or security guards had been allowed to be armed that probably would have been enough of a detterence to the two boys. Even if they still had tried it, it is doubtful as many people would have been killed and wounded.  

 This alternative is not completely hypothetical either. A few years ago at the Appalachian School of Law, a student came to school with a gun. He shot the dean, a professor, and another student. He was then subdued by three classmates that had run to their cars to get their own guns. A Columbine-like tragedy had been avoided. 

 Compare Columbine to the shooting at the Appalacian School of Law and the answer is obvious: we need more guns, not less.