Preemptive Warfare

I've read some stuff over the years about how the Bush Administration is so fond of the doctrine of preemtive war and that Darth Cheney's threshold for preemption is a 1% chance of something bad happen.

Some years ago, in a flat state between the Alleghenies and the Rockies, I was gassing up my little Honda Civic. A pickup truck pulled up alongside the other side of the pumps. The driver got out to fill up the truck and the various pieces of gas-powered equipment he had in an open-bed trailer.

The driver had a shaved head and spiderweb tattoos on both of his elbows.

My understanding at the time was that such tattoos were an indicator that one was a white supremacist or suchlike and that the person so inked had either participated in a gay-bashing or an assault on a minority.

Given the 1% Doctrine, would I have been morally justified in shooting his ass right then and there? (I'm not talking about "legally justified", I know the answer to that.)