Omar Khadr’s trial before a military commission at Guantanamo has reportedly been delayed once again. This time, Khadr’s attorney has suffered some illness and the trial has been put on hold for thirty days, according to Agence France-Presse.

Before this latest delay, the prosecution did get to show a video of Omar Khadr assembling and planting improvised explosive devices (IEDs) along with his al Qaeda compatriots. The video is certainly one of the more damning pieces of evidence against Khadr.

So, it is no surprise that Khadr’s attorneys tried to have it excluded. They argued that the video was only discovered after Khadr was indirectly threatened with rendition and abuse during an interrogation. They called the video “fruit of the poisoned tree.” But how can that be?

It is one thing to argue that Khadr’s confessions, in which he admitted throwing the grenade that killed an Ameican medic, were the result of coercion. (The military judge disagreed with Khadr’s counsel on that score. An FBI agent testified that Khadr’s interview sessions were friendly and there was no hint of coercion. Khadr’s confessions were allowed as evidence.)

But it is quite another thing to argue that a video, made by al Qaeda before Khadr was captured, and in which Khadr is shown willingly putting together explosives, is somehow “tainted.”

The contents of the video are in no way dependent upon the circumstances of Khadr’s interrogations.

That did not stop Khadr’s lawyers from arguing that the video is “fruit of the poisoned tree.” Detainee lawyers are aggressively using this legal theory to try to exclude incriminating evidence. They have had much success using this tactic in habeas proceedings. Federal judges frequently do not require any proof or hard evidence of abuse.

If a detainee, or even a detainee’s lawyer, submits an affidavit saying that abuse occurred, then in many judges’ minds that is enough. And the U.S. government has done a poor job of rebutting the argument. In many cases, the government just says that al Qaeda operatives are trained to lie about their treatment in custody and so there is no reason to take their claims at face value. In many instances, the government does not offer specific rebuttals to the most outrageous allegations of abuse, even when the government knows that the alleged abuse did not occur.

For example, former Gitmo detainee Binyam Mohamed claims that his genitalia were sliced with a razor repeatedly for more than a year while he was detained in Morocco. Sources I’ve spoken to say that never happened, and the government knows it. But prosecutors are reluctant to take on the issue because it involves exploring the CIA’s interrogation and detention practices further in a court setting. And the CIA’s practices did include such tactics as sleep deprivation. But by failing to rebut Mohamed’s ridiculous allegations the government forfeits control of the evidentiary pool to defense lawyers. In one habeas proceeding involving one of Mohamed’s fellow al Qaeda trainees, a federal judge repeated Mohamed’s story as if it was completely true, and then excluded the incriminating testimony Mohamed gave against his former fellow detainee.

Therefore, the “fruit of the poisoned tree” argument is a winning tactic for defense lawyers most of the time. It didn’t work for Omar Khadr’s lawyers, however.

Excerpts of the video starring Khadr were shown by CBS News’s “60 Minutes” a few years back. You can view the "60 Minutes" segment online. If Khadr’s lawyers had gotten their way, Khadr’s military commission would not have been able to see the video during the trial, even though the American public had seen parts of it on broadcast television already.

Thomas Joscelyn is a senior fellow at the Foundation for Defense of Democracies.

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