Good criminal defense attorneys are seldom deterred by futility, so it's reasonable to expect that KSM's lawyers will make all the arguments there are to make: They'll allege a violation of KSM's right to a speedy trial, claiming that the years he spent in CIA detention and Gitmo violated this constitutional right. They'll seek suppression of KSM's statements, arguing (persuasively) that the torture he endured—sleep deprivation, noise, cold, physical abuse, and, of course, 183 water-boarding sessions—make his statements involuntary. They will insist that everything stemming from those statements must be suppressed, under the Fourth Amendment, as the fruit of the wildly poisonous tree. They will demand the names of operatives and interrogators, using KSM's right to confront the witnesses against him to box the government into revealing things it would prefer to keep secret—the identities of confidential informants, the locations of secret safe houses, the names of other inmates and detainees who provided information about him, and a thousand other clever things that should make the government squirm. The defense will attack the CIA, FBI, and NSA, demanding information about wiretapping and signal intelligence and sources and methods. They'll move to dismiss the case because there is simply no venue in the United States in which KSM can get a fair trial.
All of these motions and three dozen more will be either denied or denuded of any significant impact on the disposition of the case. The speedy-trial argument will fail. Important documents will be scrubbed and redacted to the point of unintelligibility or will be ruled irrelevant. The motions to dismiss will all be denied. And though some of KSM's statements will be suppressed in order to preserve the appearance of impartiality and integrity, plenty of the most damming ones will remain admissible. While condemning in stern language the terrible treatment of KSM and denouncing water-boarding as beneath the high standards of our justice system, the trial judge will nonetheless admit into evidence statements made by KSM in subsequent military tribunals, along with those made to a so-called “clean team” of interrogators, rendering all the suppressed evidence utterly insignificant.
In an idealized view, our judicial system is insulated from the ribald passions of politics. In reality, those passions suffuse the criminal justice system, and no matter how compelling the case for suppressing evidence that would actually effect the trial might be, given the politics at play, there is no judge in the country who will seriously endanger the prosecution. Instead, with the defense motions duly denied, the case will proceed to trial, and then (as no jury in the country is going to acquit KSM) to conviction and a series of appeals. And that's where the ultimate effect of a vigorous defense of KSM gets really grim.
At each stage of the appellate process, a higher court will countenance the cowardly decisions made by the trial judge, ennobling them with the unfortunate force of precedent.