Okay, I didn't want to weigh in on this, but it's hard not to.
This is a terrible tragedy. The first and most important thing is medical, moral and legal support for the survivors. If that wasn't the first thing you thought of, you're an asshole.
I was going to leave it there, but I'm being bombarded with angry posts from people.
Now, it's perfectly understandable (speaking of the public, not the participants) to feel shock, outrage, impotence, fear.
So, the obvious solution is to BAN ALL THE GUNS!!!!! And I'm a lunatic/hater/right wing retard for owning and using them.
Which is the same bullshit we hear every time there's a crime.
Look, some asshole stabbed a bunch of kids in China yesterday. The worst school killing in the US was in the 1920s and featured home made bombs. Some other asshole drove his Cadillac into a schoolyard in the 1980s. If someone wants to kill people, there are plenty of ways to do so. Whether or not guns exist, killers will.
As to banning, it'll be about as successful as prohibiting booze. Guns are a 13th century technology. They can be built in a modestly equipped garage, and they are. Peasants in Afghanistan make them in caves. So any talk of banning is ridiculous.
Also, guns are illegal in schools, so this asshole was breaking the law! Gee, I guess murderous cocksuckers don't care about laws. How about that?
In fact, MURDER is apparently illegal in the US, and also not well-regarded.
Guns exist and you can't make them go away. If guns didn't exist, there are plenty of other ways to kill people, which were used very effectively for tens or hundreds of thousands of years before guns existed.
Let the families grieve, pray for them if it makes you feel better, and don't attack the 94 million gun owners who didn't kill anyone today.