Pre-emptive wars are never justifiable. Note that one of the great pre-emptive attacks of all time was the Japanese attack on Pearl Harbour! The Japanese did it because they perceived that the USA was cutting off their international supply sources of oil and steel, thus rendering them impotent militarily within a year or less if they did not attack. Accordingly, they pre-emptively attacked while they still had enough oil to fight, launching a war that most of their naval staff doubted they could possibly win in the long run.

And it's known as "a day that will live in infamy". The day that "Shock and Awe" began should also live in infamy, because it has caused nothing but suffering and disaster.