No one is "tolerating" school shootings, no one wants them to happen. Both sides of the gun debate agree on the fact that they don't want people to be murdered, they just have different opinions on how to try keeping people safe.
Sorry, as I suggested earlier, Charles Whitman to now - 49 years (how old is Obama, out of interest). What significant changes have been made to prevent these tragedies, and what measure of success have they enjoyed.
None, and none seems to be the answer.
However, in the preceding 49 years, the US has tightened up car emissions (!), driven through several equality initiatives, put a man on the moon. Carried out several significant military engagements, and passed laws which are still in debate with regard to their constitutionality. Smoking has been reduced, and even with the frankly staggering reduction to now, is still talked of in terms of elimination. The US has pushed for and been open to reducing the worlds nuclear arsenal - more than twice (SALT 1/2). The US has been instrumental in helping police the internet, and locate paedophiles and bring them to justice across the globe.
To someone who would like to consider themselves an educated observer, it seems a fair conclusion that, when the hand-wringing is over, and there's another story, the US returns to tolerating spree killings.
I appreciate the gun-ownership debate has a different tone in the US. A lot of non-USians (especially the UK) simply don't appreciate the revolutionary crucible which forged the culture which emerged. For better or worse, the UK just doesn't "do" revolutions.
I find that figure - 49 - curious, as it's close to my age. And one thing ages gives you, is a literal sense of history, because I was there. Someone 20 - even 30 - years old, may be taken in by politicians who try to give the impression that something has "been important for years". Yeah, right. Important enough to talk about, but not quite important enough to do anything about.