>>No.
>>Alan the art of "assassination" requires an element of surprise and secrecy.
>>Bombing the hell out of an enemy hideout is just part of war.

>What if I do both - declare war and then kill the opposing leader by stealth? Being that it probably makes little difference to the assassinee, and since it was a pre-emptive strike and not a response to a declaration of war, it sounds like semantics to me.

Nope.
By declaring war, you are implying that you'll , one way or another, take down the leader. So element of surprise is gone and the leader is on the run in hiding.

If you're referring to the Iraq war, remember, with Iraq, the first gulf war never ended. It was just a cease fire.