Says who? The prosector must present enough credible evidence to show that he's a legitimate suspect. The prosecutor(The U.S.) must respect the soverignty of the nation just as he must respect the soverignty of any home in America. He cannot enter without enough evidence to convince a judge that he has a resonable belief that he has the right person.
He may not kill the family for demanding that the evidence be presented, nor may the government prosecute a war killing the man's countrymen without due process.
By bombing and killing Afghanis other than bin Laden, we are unjustly denying them due process. That is as far from libertarian as it gets and I am disgusted that you want to justify such behavior.
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.