Was the shooting at Fort Hood a "terrorist act"? Sure, I'll agree to that. But of course, so was Columbine. And the Virginia Tech killer. And that guy who shot up the Aerobics class. These are all terrorist acts. It's all about powerless people trying to show that they're not as powerless as they seem; and of course, we're all supposed to not notice what it is that gives them their power (Hint: It's guns.).
But how to stop these things. You can't. This isn't something you can trace back to a terrorist training camp. We can't wiretap their minds...yet. And no number of invasions will make it possible for us to stop these events from occurring. Rampages happen. People flip out. You can't stop the crazy. I suppose one rational answer would be to limit their ability to obtain weapons of mass destruction, but short of that, there ain't much we can do. There will always be crazies who kill people.
And this isn't a Muslim thing, or a school thing, and it might not even be a gender thing (though rampaging murderers tend to be male). The primary issue is that we have an imperfect society that makes certain people feel less powerful than they imagine they deserve. And they get roped into a warped way of looking at life, that blames everyone else for their own problems. They are their own worst enemies and project that out upon the world; seeing hatred everywhere because they hate so much.
And the question isn't why this keeps happening, but why this doesn't happen more often. Killing people is easy. And if someone feels pressured into thinking that violence is their only option, then they're going to use violence. Our goal isn't to make it so that people can't rampage, but rather, to limit the number of these rampages. And while I do think there are some good things that can be done in this regard, I seriously can't imagine how any of them would come from Joe Lieberman's committee.
There is one other alternative to this: Aliens. Shape-shifting aliens invaded Fort Hood and Hasan was the only one who figured it out and was trying to wipe out the alien menace before they took over. He killed most of them, but the Colonel stopped him and had him arrested. It turns out the Colonel is the head alien! After the arrest, the aliens flood the media with negative news about Hasan, saying that he's an Islamic extremist who hates America; making him the most hated man in the country.
At some point Hasan escapes and a giant manhunt ensues to capture him. He's taken in by a group of Klansmen who have temporarily suspended their hatred of non-whites to focus instead on non-humans. The final battle pits the alien-controlled Fort Hood against all the militias, separatists, neo-confederates, and anyone else with a shotgun. They come charging in on their pickup trucks, guns blazing. Hasan leads the charge. It's a tough battle, interspersed with violence, mayhem, and zaniness.
Finally, just as it looks as if Hasan is about to be killed by the Colonel, the hottie hillbilly girl kills the Colonel. Hasan rushes up to her, they look at each other momentarily, then kiss. Love conquers all.
Oh, and the sequel involves Hasan taking an alien ship back to the home planet, to wipe them out before they wipe us out. And in the final movie, racial harmony ends after the defeat of the aliens, and race wars break out across the globe. It turns out aliens are involved in this, and Hasan has to bring the ancient alien ruler to earth, in order to end the assault. But is he in time... And yes, I really am too good at this.