The trial of the only suspect charged in connection with the 11 September attacks is facing a setback.
The Bush administration is defying a judge's order to allow the man, Zacarias Moussaoui, to interview an al-Qa'ida suspect. Mr Moussaoui is acting as his own lawyer and says calling Ramzi Binalshibh - accused of masterminding the attacks on New York and Washington - could help him to prove his innocence. The government's refusal could mean the case is thrown out.
Leonie Brinkema, the judge, concluded that Mr Binalshibh might support Mr Moussaoui's contention that he was not part of the 11 September conspiracy and ruled that the defendant should be allowed to question the witness through a satellite link. Mr Binalshibh, arrested in March in Pakistan, is being questioned at a US facility overseas.
But the government argues that although it intends to use evidence from Mr Binalshibh in its case against Mr Moussaoui, it will not allow the defendant to question him on the basis of the threat to national security. In papers filed at the Federal District Court in Alexandria, Virginia, the Attorney General said Mr Binalshibh's participation in the trial "would necessarily result in the unauthorised disclosure of classified information".
Judge Brinkema can now dismiss the case, throw out some charges, exclude government evidence or tell jurors that the government refused to provide certain evidence.
The government's decision could mean the criminal prosecution is dropped and the case sent to a secret military tribunal, even though the government, looking for a public victory, has long wanted Mr Moussaoui, a French citizen charged with conspiracy, tried in the civilian justice system.Reuse content