Salim Ahmed Hamdan's prosecution highlights yet again the foolishness of the Bush administration's experiment with military commissions. Rather than pursue terrorist suspects through the regular civilian or military courts, the administration stubbornly insisted on building a system from scratch. Predictably, the commissions attract more attention to their unfairness than to the alleged crimes of the suspects before them.

The primary motive for the military commissions was to allow the introduction of testimony secured by coercion. Although the commissions' rules reject torture, they permit evidence gained by equally illegal "cruel, inhuman or degrading treatment." Then, to facilitate covering up such savagery, the commissions allow hearsay – for example, a supervisor reading a bland transcript of an interrogation, rather than the interrogator facing cross-examination about the pain and suffering he inflicted. No legitimate court would admit such coerced testimony.

So what did these unfair rules get the administration in the case of Hamdan, Osama bin Laden's former driver? It gained the right to introduce evidence that Hamdan admitted pledging allegiance to bin Laden during an interrogation that the defense argued was coercive. To the jurors' credit – but hardly the commission rules that admitted it – they seemed to reject the dubious evidence of that pledge, finding that Hamdan had never joined a conspiracy to commit terrorism. Instead, they found him guilty only of providing services – his driving – to a terrorist organization.

Even that conviction, and the modest sentence imposed, are now in jeopardy. The crime of providing material support to a terrorist group could have been prosecuted in federal court. But it became an offense under the military commissions only after Hamdan was arrested, suggesting a possible constitutionally prohibited ex post facto prosecution.

Hamdan is a minor character, but major prosecutions are coming, including of alleged 9/11 mastermind Khalid Sheikh Mohammed. It is not in America's interest to let Mohammed portray himself as a martyr of an unjust system. The military commissions should be shut down, and all prosecutions moved to regular courts.