Stephen Foley: Gun lobby groups ensure America will never change right to bear arms
A Wall of Remembrance at the memorial to the Columbine massacre in 1999 is studded with granite squares, each engraved with a reminiscence or reflection from a student, teacher or emergency service worker affected.
Only one quotation is unattributed. It reads: "It brought the nation to its knees, but now we've gotten back up, how have things changed; what have we learned?"
The temptation, after a new mass killing in another Denver suburb, is to whisper in reply: "Not very much in 13 years."