When US president Barack Obama set out his national security policy on May 21, he divided the 240 or so remaining prisoners in Guantánamo Bay into five categories (see inset). If the Netherlands should decide to take in some of them, as prime minister Jan Peter Balkenende hinted at this week during a visit to Washington, they would come from the fourth category.

They are a group described by president Obama as "prisoners of whom we have determined that they can safely be transferred to a third country". At the time, the Obama administration said fifty such prisoners had been cleared for transfer.

Guantánamo à la carte Category 1: eligible for criminal prosecution in a US federal court; a very small number. Category 2: to be prosecuted under the controversial system of military courts; a few dozen. Category 3: ordered released by a US judge; 21 prisoners. Category 4: eligible for transfer to a third country; by far the largest group. Category 5: detainees who are seen as a real threat to the US. The administration would like to see them prosecuted, but there is a good chance this will fail because evidence against them was obtained through torture. President Obama has said they will not be released under any conditions.

Meanwhile, Obama said his government is "in constant talks with a number of countries about transferring prisoners back to their own countries for detention and rehabilitation". The roughly one-hundred Yemeni prisoners in Guantánamo fall in this (sub)category. Washington is reluctant to send them back because it has little confidence in Yemen's rehabilitation programme for terror suspects, and prison escapes are common there. The Americans wants Yemen to get its house in order before it sends the prisoners back.

Washington is worried that some Guantánamo prisoners might (re)join Al Qaeda or other militant groups if they are released. According to the Pentagon, one in seven Guantánamo prisoners released so far has since been involved in terrorism or other militant activities. The main Taliban commander in the south of Afghanistan, for instance, is alleged to be "former prisoner number 008".

The Americans are also wary of prisoners being tortured in their countries of origin. This could happen to the Uighur (Chinese Muslim) prisoners. Five of them were taken in by Albania in 2006, four others went to Bermuda. Another tropical island, Palau, has offered to take in seventeen Uighurs.

If Obama is seeking the help of other nations in closing Guantánamo it is because of the opposition at home over allowing Guantánamo prisoners on American soil. When it was announced that a small number of them would be locked up in 'supermax' prisons in the US, there was uproar even in Obama's own Democratic party.

But many other countries are equally reluctant to take in prisoners from Guantánamo. The European Union failed to reach a common stand on the issue, leaving the decision up to the member states instead. Belgium only wants to take in prisoners who might otherwise be tortured in their own countries. Italy has agreed to take in three 'specific' prisoners. France will take in one Algerian and will study other requests on a case by case basis, as will Portugal, Spain, Sweden, Finland and Ireland.

Many detainees in Guantánamo ended up there by way of the US military base at Bagram near Kabul, Afghanistan. With the announced closure of Guantánamo, Bagram has gone from being a transit point to a final destination for terror suspects. More than 600 'enemy combattants' are currently being held there without trial.

According to the rights group Human Rights Watch, prisoners at Bagram have even less rights than those at Guantánamo. They have no right to an attorney, for instance. An American federal judge ruled in April that some prisoners at Bagram will be allowed to contest their detention. They are non-Afghans arrested outside Afghanistan who were taken to Bagram and have been kept there for an "unreasonably long period of time". The Obama administration is appealing the ruling.

Washington is putting Bagram on a different footing than Guantánamo because it is located in a war zone. Last month two US soldiers were killed there by mortar shells. The US wants to enlarge Bagram prison to raise its capacity from 1,000 to 2,100 prisoners.

There have been many reports over the years about ill-treatment of prisoners at Bagram. Last month the BBC released its own investigation about 27 Afghans who were at Bagram between 2002 and 2008 and who say they were beaten, exposed to extreme heat and cold and threatened with death. The Pentagon has denied the allegations. President Obama banned torture shortly after his inauguration, but it is not known to what extent conditions at Bagram have changed since then.