Six al-Qaeda suspects in US custody can be tried before a military tribunal, President George Bush has decided. The BBC's Steve Kingstone in Washington explains more.
What is the US case for using military tribunals?
These men were arrested during a war and should therefore be subjected to military justice, the US argues. As enemy combatants of the United States, the government says they do not deserve the full protection of the US legal system.
Also, these are highly-sensitive terrorism cases. The prosecution is relying on classified intelligence which needs to remain behind closed doors. Otherwise the US fears ongoing intelligence efforts might be compromised.
It argues that to put any of the alleged terrorists publicly on the witness stand might give them the opportunity to send coded messages.
Have tribunals been used before by the US?
Yes. George Washington first used them during the Revolutionary War. The practice continued until after World War II when German and Japanese officials were prosecuted by tribunals.
At that time, the US Supreme Court ruled that military tribunals were legal. But they have not been used them since.
George W Bush revived the idea after 11 September to prosecute terrorism cases involving non-Americans.
How will tribunals differ from normal trials?
Unlike a conventional trials, military tribunals are held largely in secret. A panel of three to seven officers acts as judge and jury. Defendants are represented by military lawyers.
The normal rules of evidence are relaxed, which tends to favour the prosecution.
Who is going on trial?
Six men have been designated as eligible to face trial by military tribunal. All are non-US citizens, although the Bush administration has declined to give their names or nationalities.
The UK Foreign Office says two of the men are British.
President Bush believes the men have all been members of al-Qaeda, or otherwise engaged in terrorism against the US.
When will the trials take place?
At this stage, no final decision has been taken about whether the trials will go ahead.
The next step is for a chief prosecutor to draft charges against the men.
The US Deputy Defence Secretary, Paul Wolfowitz, will then make a decision as to whether to proceed.
What objections are being raised?
The American Bar Association and human rights groups point out that the US has, in the past, condemned other countries for using military tribunals.
They are also concerned that defendants will not receive the same rights as defendants in conventional trials, and that the media may not be granted access to cover any trials by tribunal.
Some politicians and commentators have also argued that holding military tribunals will damage US relations with key allies like Britain, and further tarnish the reputation of the US in the Arab world.
Holding secretive legal proceedings, they say, goes against the values of freedom and openness that underpin the US-led War on Terror.
What sentences can be imposed?
The panel of military officers can find a defendant guilty by a two-thirds majority.
Is President Bush likely to allow a death sentence to be carried out?
Quite possibly. The attacks of 11 September 2001 remain the defining moment of his presidency and prosecuting the War on Terror is his top political priority.
Mr Bush will come under the greatest pressure to use the death penalty for suspected al-Qaeda ringleaders. These six men may not fall into that category.