I don't share your confidence.
A well planned attack creates international privacy issues when you can hide behind laws or hide behind the need for a subpoena. Do that a few times, and you've got a complete bureaucratic nightmare.
I don't share your optimism.
The US federal government has granted itself (under US law) the authority to investigate, pursue and take into custody, and prosecute
anybody who has committed a crime against the United States (or one of its citizens) anywhere in the world regardless of the country it was committed in or the citizenship of the person accused.
The US government invaded Panama and overthrew its government to arrest General Noriega on drug trafficking charges. We have an unknown number of prisoners rotting in a concentration camp on a military base in Cuba - a country that is officially hostile towards the US. We just walked into the country of a supposed ally, without so much as a "by your leave," for the express purpose of killing Osama Bin Laden.
Regardless of the "rightness" or "justice" or "necessity" of any of the above (and there are differing opinions) I think it's fairly obvious the United States does not feel constrained by treaties, international law, due process - or even it's own Constitution when it feels US interests are being threatened. (Like that famous movie line said: Badges? Badges? We don't need no stinking badges!
Nor does any other major power these days.
9/11 changed everything. For everybody. Look around at all the governmental meddling, firewalling, and network censoring that's either planned, or already being done, worldwide. It's even happening in the so-called democratic nations.
! You're supposed to be our resident cynic. Do you really believe the US is gonna let some inconvenient law or due process argument stop them from nailing someone who's thumbing their nose at them?