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."
The killing spree at Columbine High School, in which 12 children and a teacher died at the hands of two senior students, prompted a national debate over gun control laws, but led to no new national legislation and no substantial changes in Colorado either.
Today, the state has among the country's laxest rules on the purchase of firearms. Local police believe James Holmes unleashed his terror in the Century 16 cinema in the suburb of Aurora last Friday using an arsenal of four guns and 6,000 rounds of ammunition that he obtained entirely legally.
Again, the atrocity has prompted a national debate. But debate is all anyone expects, not action.
"What do they stand for, and why aren't they standing up?" New York's mayor Michael Bloomberg asked of the two presidential candidates, Barack Obama and Mitt Romney.
Other politicians are increasingly wary of weighing in in favour of anything that might circumscribe the Second Amendment right to bear arms, in the face of the National Rifle Association's massive lobbying firepower. Gun control advocates are on the back foot almost everywhere in the US.
The Columbine memorial is a hauntingly silent circle, carved into the hillside of a popular park behind the high school.
Aaron Rizzuto (27) is reading them, one by one. He expresses a typical fatalism about the chances of tightening gun laws, much as he personally would like to see people put aside a Second Amendment that was adopted in 1791 at a time of Revolution.
"It's as if everyone thinks the King of England is going to be knocking on their door any day," he says. "I think we are a bit past that, but there's not enough people, with not enough power, to have our voices heard."
Pat King's daughter was nine at the time of the Columbine massacre -- the killings in Aurora stirred memories of that day and made him cry again.
"These weapons, the automatic and semi-automatic weapons, these are not for hunting. They are for killing people, that is all. But this is America, there is a right to bear arms and you can't take their guns. To do so, you would have to start with tackling the NRA first. They push this stuff, and they don't care what happens."
The NRA is undoubtedly one of the most powerful lobbying organisations in the US, and it is not hesitant to divert campaign contributions to defeat advocates of gun control.
Many Democrat operatives believe Al Gore's support for gun control lost him key states in the 2000 presidential election, largely because of NRA opposition. The organisation has raised $9m (?7.4m) already for this November's elections.
The Long Island Railroad massacre in 1993 was the last time a mass killing really moved people to demand tighter restrictions, leading to a 10-year ban on assault rifles of the kind used at Century 16. But the ban expired in 2004 with little congressional effort to renew it.
EVEN the shooting of one of their own, the Arizona Congresswoman Gabrielle Giffords, who was almost killed in a mass shooting in Tuscon last year which took the lives of six others, prompted no new laws. In 2010, the Supreme Court ruled a ban on handguns unconstitutional, the vote split along ideological grounds.
Support for once-popular measures, such as a ban on handguns, has fallen to a 50-year low of 26pc.
Senator John McCain pointed to Anders Brevik's massacre in Norway a year ago as evidence that even tight gun laws will be broken by men who want to create terror.
The tragedy in Aurora has once again knocked a nation off-balance. When it gets back up, how will things have changed? Those who want to use Friday's killing spree to shake some sense into America's gun laws might as well be talking to a wall. (© Independent News Service)
James Eagan Holmes, the man suspected of shooting dead 12 people in a cinema in a Denver suburb, applied to join a local gun range last month, but the "freakish" greeting on his voicemail made the club owner decide to turn him away.