Says Reason. Your post, when it talks of prosecutors presenting evidence, commits the fallacy of placing jurisprudence before the natural law. The reverse is true: natural rights exist regardless of the judicial superstructure to enforce them. When the matter falls outside of a single jurisdiction, as is the case with any war, the justice of the war would depend on the tenets of the natural law as we interpret it in our minds.
In this task, bin Laden's case presents no difficulty unless you warp the matter with enough pointless references to "sovereignty". Bin Laden caused a massacre to happen and he took the country og Afghanistan hostage so that he and his leutenants escape justice. Individuals who are victimized by that and fear another attack (which bin Laden promised on television) deputized the US military to destroy his network. When civilians are placed, or place themselves in the way of our retaliation, which is directed at Al Qaeda, they will be harmed. We have just cause, just "sovereign" (government) and just methods.
You still haven't shown that there is evidence which warrants these actions. A white paper by Tony Blair who does not have the U.S. best interests at heart (nor the constitution) is not sufficient.
Where's the beef? They won't even show the American people this evidence. That in itself makes it suspect apart from the fact that they won't declare war. They can't because Afghanistan hasn't done anything to the U.S. which warrants a war.