Ironically enough, that made Kirk as dangerous as Khan. Feeling superior, not bound to orders, regulations and all the moral principles which, in theory, were the basis of the Federation's code of conduct. Barely any different than warmongering admiral Alexander Marcus; being reckless, aggressive and presomptuous as to take the chance to start a war just over a question of vengeance and will for bloddshed. In Perdition's flames indeed.Jedi Master Spock wrote: Third, even if the admiral is searching for casus belli for a shooting war with the Klingons, launching an illegal mission to Qo'noS is a crap plan. After all, nearly every line starship captain and officer would swiftly identify those orders as illegal and liable to start a war. We saw evidence of that in how every Starfleet officer who isn't Kirk or the admiral reacted to those orders. Scotty even resigned, and with anything less than Kirk's cult of personality among the bridge crew, the rest of the officers aboard ship probably would have followed suit. Check three for safety.
Khan looks like an abused nice buddy in comparison, in that movie.