It is often said that hindsight is 20/20. Even in the VaTech tragedy there are those who, in hindsight, say that this could have be averted if the murderer has been helped in some way or institutionalized earlier, if the administration had locked down the school after the first two murders, if other students had been allowed to carry concealed handguns to defend themselves and others, or if there existed tighter gun control laws in the state of Virginia.
This is, like the wisdom of almost all hindsight, patent nonsense. It is just as likely that if any of those changes in history had been made, the murderer may have slain 100, escaped, and duplicated the incident on 10 other campuses throughout the country.
Humans, confusing themselves for God, regularly feel that they can manipulate the script like the director of a movie and bring to bear the ending that is more pleasing to them. Foolishly they do not see that their changes bring into play other unforeseen variables that result in an end far from the intended result and regularly much worse than that of the original.
So often is the case with political action. Legislators or judges whose vision within the greater scheme is only 'seeing through a glass darkly', attempt to play God and direct the 'movie' of human society. So many of their actions have resulted in disasters. Yet, in their blindness, they fail to learn and follow the adage, 'If at first you don't succeed, try, try again.'
Whether attributed to Ben Franklin or Albert Einstein, the following is more applicable: "The definition of insanity is doing the same thing over and over and expecting different results."
So, in hindsight, I would say that the only way that this tragedy would have been averted would have been for someone to murder Cho Seung-Hui before his actions at the university. But then again, perhaps, 7 angry relatives or friends might have taken vengeance and slaughtered even more. I'm not God and therefore lacking in omniscience, omnipotence, and omnipresence. If there were 9 of me on the U.S. Supreme Court, or 50 of me in the U.S. Senate, or 435 of me in the U.S. House of Representatives, or even 6 billion of me, my hindsight, as well as my ability to direct reality would be laughable.
Pitiful, just pitiful.