Probably the most difficult parts of this will be to define who is responsible and what exactly constitutes as justice.
Killing them like osama, blasting them with a drone or detaining them in gitmo means the terrorist have won, because they have dragged the system down to their own level.
Also it still may be not an act of terror. Just some wackos that decide it is fun to blow stuff up. They don't have a need for a political agenda or ideology to do stuff like that.
Also murder is crime in Pakistan ... so if there was Pakistani rule of law the navy seals are murderers.
On the nuts and bolts, the distinction you're trying to draw is also moot; Congress explicitly authorized:
That the President is authorized to use all necessary and appropriate
force against those nations, organizations, or persons he determines
planned, authorized, committed, or aided the terrorist attacks that
occurred on September 11, 2001, or harbored such organizations or
persons, in order to prevent any future acts of international
terrorism against the United States by such nations, organizations or
About the best I think you can say is that striking Bin Laden could have been an act of war against Pakistan. Somehow, I don't think they're going to follow up on that.
In any case, what Osama did would clearly be an act of war if he had been a general acting on the orders of a government. So what makes it not an act of war just because he's acting on behalf of an entity that isn't a sovereign state? Surely, it is most logical to measure the justifiable response to an action in terms of the nature of the action itself, not the political affiliation of the actor.
Finally, as you note, it's hard to say that there is any rule of law in Pakistan. Laws only have meaning to the extent courts have jurisdiction to enforce them. "Murder" isn't a universal constant--it's a law defined in the context of some sovereign entity's legislative jurisdiction. Killing a terrorist on the battlefield is not murder if there is no court that has jurisdiction over the actor that would call it murder. Indeed, it seems utterly non-sensical to me to argue that someone like Osama, that has rejected the criminal jurisdiction of any state, can turn around and claim the protection of the laws of that state.
People in Europe are learning right now how not awesome it is to get yourself into binding international frameworks with people who are connected by incomplete legislative and executive jurisdiction, and whom often have dramatically different national priorities and values.
In any case, it's arguably unconstitutional for the U.S. to support international courts. If Congress signed up for a treaty binding us to the decisions of say the IJC or ICC, would those decisions be reviewable by the Supreme Court? If so, then accepting jurisdiction would be redundant, since the Supreme Court is perfectly competent to adjudicate disputes under "international law." If not, that would arguably be a separation of powers violation: Congress signing us up to accept the superior jurisdiction of a foreign court whose judgments couldn't be reviewed by what is supposed to be the court of last resort: the Supreme Court.
Those were acts of war, and prosecuted under those rules (international law, Geneva Convention, etc), rather than domestic criminal law.
I don't understand the trouble you have with the Osama situation. The US attempted to apprehend Osama so they could bring him to justice but he resisted and was shot to death. How would you have handled that situation?
And yet I think that the most powerful and expensive military in the world should have found a way to properly extract him. I am not convinced that the way it was handled brought the needed closure to the 9/11 events. It just proved that US was better at targeted killing than Al Caida or whatever that ragtag bunch was called.