Ok, I'll play devils advocate. Everyone says something has to be done. Well, what is it that has to be done. Yes, they could stop the sales of any further semi automatic's, but, what does one do with the millions of rifles and I would estimate the multi millions of high capacity magazines that are already out there? See, short of kicking in doors to confiscate, I see no way to cure this.
Of course, my own opinion is maybe... just maybe if certain people would do their job, a lot of nut cases wouldn't be falling through the cracks in the system that we already have in place. (see something, say something won't work if people who should, don't follow up on these actions)
Never ceases to amaze me how law abiding citizens should have to shoulder the burden or be punished for the actions of a very tiny part of the population.