One year ago today, the unthinkable happened.

It wasn’t like there hadn’t been school shootings before — there had already been a shocking number of them.

Springfield, Ore., Jonesboro, Ark. — the datelines run through our memories; each school shooting topped the last in terms of horrific violence and unanswered questions.

But nothing could have prepared the upscale community of Littleton, Colo., for what happened April 20, 1999, in the socially segregated Columbine High School.

Two seniors, Eric Harris and Dylan Klebold, entered their high school brandishing shotguns. In a massacre that last several hours, the two killed 12 of their classmates and a teacher. After doing the bulk of their killing in the school’s library, Harris and Klebold then turned their guns on themselves.

The biggest high school massacre in American history has left more confusion than comfort. The Columbine community pointed fingers, first at the murderers’ parents, then at gun-control legislation, even at pop culture and entertainers.

One year later, it is difficult to judge what happened in Littleton. Many are still struggling to make heads or tails of the situation, but some good has come out of what happened.

A dialogue was opened, the first in a very long time, about how high school students really treat each other. Harris and Klebold can never be excused for what they did, but many of their peers reported they were badly abused mentally, and in some cases, physically by classmates.

A teenager, whose mental makeup is arguably already fragile, shouldn’t have to be subjected to this. Whether it’s a jock culture, a class war or a teaching staff that refuses to do anything about it, these conflicts will always be in high school as they are the real world.

But they should never be ignored again. It doesn’t take much for even the most sound-minded person to snap.

Even if only part of what allegedly happened to Harris and Klebold inside the walls of Columbine actually occurred, it’s a wonder they repressed their rage as long as they did.

The debate on gun control was also reopened, and security at high schools across the nation was beefed up. Whether these reactions are a good thing remains to be seen — in both cases, some activists and administrators have gone to extremes, but at least the issues are being examined.

Columbine cannot and should not be forgotten.

Hopefully people have learned something from it, and as long as that something doesn’t entail blaming pop culture for their own children’s behavior or being unnecessarily paranoid or fearful, that’s a step in the right direction.

Iowa State Daily Editorial Board: Sara Ziegler, Greg Jerrett, Kate Kompas, Carrie Tett and David Roepke.