So we've got this country where the leader (we'll call him Mr X) assumed power in a dubious manner. He's been building up the military, and is pretty obviously going to use it to attack somebody. He begins talking smack about another country. Now this other country is not a nice place, in fact the head of state is a rather unpleasant dictator. Mr X begins massing armed forces for an attack on his selected enemy. He begins making wild claims about how evil and terrible the other country is. He lies a lot. After assembling a coalition of helpers he attacks the country and conquers it in an unprecedentedly quick manner. The locals are not all that pleased and begin a multi-year program of resistance. Mr X responds by torturing and killing large numbers of the people who live in the country he invaded. He goes on to invade many other countries and is eventually defeated by the united efforts of most of the rest of the world.
The consensus view is that Mr Hitler was a war criminal for waging an unprovoked war of aggression against Poland. Right up to the invading other countries part, Mr Bush's war against Iraq follows the same narrative.
Now a serious question: Is or is not Mr Bush a war criminal for waging an unprovoked war of aggression against Iraq and then instituting an oppressive occupation?