The second amendment should not and cannot guarantee the ability to commit mass murder.The second amendment states "A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed."
However nowhere in the second amendment does it state that private citizens with no interest in maintaining a militia shall be guaranteed the right bear arms.The events at Sandy Hook elementary, Columbine High School, Virginia Tech University, Clackamas Town Center in Portland, The Century Movie Theater in Aurora, and so many more, were all perpetrated by individuals whose sole purpose of gun ownership was to inflict harm on innocent people, NOT to provide security to a free state.
Enforce the Second amendment as it is written.