By Paul Reynolds
World affairs correspondent, BBC News website
President Bush's decisions over detainees in the "war on terror" go some way towards meeting criticism of his policy but not the whole way.
The president's moves will probably reduce that criticism but they will not end it.
He has acted for four basic reasons.
First, the legal imperative
The US Supreme Court ruled in June, in a case brought by Osama Bin Laden's driver Salim Ahmed Hamdan against the Defence Secretary Donald Rumsfeld, that the US Congress had to authorise military tribunals or commissions at Guantanamo Bay, not the president himself.
Bush wants to shift attention from Iraq to the "war on terror"
The court further ruled that the commissions had to offer better legal safeguards. So Mr Bush had to propose the legislation that now goes before Congress.
Second, domestic and international pressure
There had been calls on him to come clean about the secret prisons run by the CIA and to clean up the scandal over the use of harsh interrogation techniques. European countries in particular were angry about the rendition flights that ferried prisoners to and from the secret camps, reflected in a critical Council of Europe report. The inhumane and degrading treatment of prisoners also attracted huge criticism.
Third, the passage of time.
This allows the president to say that the al-Qaeda leadership in detention had given all they were going to give, so the secret camps could be safely emptied and the suspects sent to face trial by military commission under the new rules that will be laid out by Congress. However, he has two caveats. The CIA stands ready to reopen the secret camps if more suspects are captured. And he wants legislation to limit lawsuits against interrogators.
Fourth, congressional elections in November
The moves are part of a big effort by Mr Bush and his administration to switch American public opinion away from the Iraq war onto the "war on terror" and to justify the Iraq war itself as part of that campaign against terrorism.
The key concessions he has made are:
The acknowledgement of the secret camps and the statement that no prisoners remain in them. He has also acknowledged that a "tough...alternative set of procedures" were used to question them.
The improvement of the procedures under which defendants will be tried by the military commissions, which themselves will be under congressional not presidential authorisation.
The prohibitions on certain interrogation techniques, including the use of dogs to threaten and so-called "waterboarding", which gives the sensation of drowning. A new army manual issued simultaneously with the president's speech says: "Any inhumane treatment is prohibited"
However, he has not moved as far as critics wanted. For example
Human rights campaigners have called for Guantanamo to close
The secret camp programme will remain in being for possible future prisoners.
There is no timetable for the closure of Guantanamo Bay.
The military commission will be able to exclude a prisoner, under certain conditions, from being present when secret evidence is presented against them.
Evidence from torture will not be allowed, but evidence from tough interrogations not amounting to torture can, if the judge thinks it is reliable.
Although the prohibition on using inhumane and degrading treatment applies to all US officials wherever they are, it is not entirely certain that in extreme circumstances (for example if an attack was thought to be imminent), they could not apply such treatment. Mr Bush put a reservation down after the passage last year of the Detainee Treatment Act, which outlaws "cruel, inhuman, or degrading treatment or punishment", to potentially allow for this.
The president also wants Congress to define in law offences that might fall under Article 3 of the Geneva Conventions. This prohibits "outrages upon personal dignity, in particular, humiliating and degrading treatment", which he says is too vague.
President lays out his reasons
Mr Bush justified his approach by listing successes he said had followed from questioning leading al-Qaeda suspects in the secret camps.
He also spoke of the need to fight the war on terror by means of intelligence: "Captured terrorists have unique knowledge about how terrorist networks operate. They have knowledge of where their operatives are deployed, and knowledge about what plots are under way. This intelligence - this is intelligence that cannot be found any other place. And our security depends on getting this kind of information."
Critic lays out his reservations
However, the Director of Human Rights Watch, Kenneth Roth, said: "President Bush's speech was a full-throated defence of the CIA's detention program and of the 'alternative procedures' - read torture - that the CIA has used to extract information from detainees.
"Although the president adamantly denied that the US government uses torture, the United States has used practices such as waterboarding that can only be called torture.
"The draft military commission legislation he announced today would allow the use of statements obtained under coercion, and would allow the accused to be convicted on the basis of secret evidence."