Behind bars in two of Britain's most heavily guarded prisons sit 12 men the police say are too dangerous to set free, but whom they cannot charge with any crime for lack of evidence.
The prisoners, all North African terror suspects, may well soon earn their freedom, however, since Britain's top court has ruled that their detention is unlawful.
As the British government scrambled this week to pass new antiterror legislation that does not breach international human rights codes, in Madrid world leaders, academics, legal experts, and policemen met to discuss ways in which democracies can defend themselves against terrorism, while not compromising their ideals.
The challenge, said former Romanian Prime Minister Petre Roman, "is Solomonic: Do we fight terrorism or protect liberties?"
The answer, suggested many of the participants at the conference called to mark the first anniversary of the Madrid railway bombings, is that only by protecting liberties can terrorism be fought effectively.
"Upholding human rights is not merely compatible with a successful counterterrorism strategy. It is an essential element in it," UN Secretary-General Kofi Annan told the meeting Thursday.
"Compromising human rights ... facilitates achievement of the terrorist's objective, by ceding to him the moral high ground and provoking tension, hatred, and mistrust of government among precisely those parts of the population where he is more likely to find recruits," he added.
Scrupulous respect for the rule of law "wrong-foots the terrorists, forcing them to campaign not against a regime but against democracy itself, which means the rule of the people," agrees Phil Bobbitt, the US law professor who led the conference deliberations on democratic responses to terror. The terrorists can take on democracy, "but I think it's a losing strategy," he says.
Surveying improvements in world security since 9/11, Gijs de Vries, the European Union counterterror czar, said he saw bright spots, such as airline security and passport control, but warned that "serious risks" remain that demand closer cooperation between the world's intelligence agencies.
"We have to change the mental matrix from where a premium is put on secrecy to one where a premium is put on sharing," he insisted.
The Madrid conference was due to close Friday with the proclamation of an "agenda" for international action. It was expected to call on security services to treat a terrorist attack in another country as if it were an attack on their own state.
That change in mentality is under way, as spy agencies measure "the extremity of the threat," according to Philippe Hayez, deputy director of intelligence at the French intelligence agency, the DGSE, who addressed a conference in Paris this week.
He cautioned, though, that "intelligence cooperation is almost an oxymoron. Intelligence by its nature does not lend itself to cooperation."
The EU is currently drafting legislation that would require member states' intelligence agencies to work as closely with each other as they do with their own national colleagues.
"Though trust cannot be established by decree," acknowledged Joaqim Nunes de Almeida, the European Commission official overseeing the effort, "at least we can overcome the legislative obstacles" to better cooperation.
Other juridical difficulties persist, however, including the different legal standards in different European countries. British courts, for example, do not admit evidence gleaned from phone taps, a defense of civil liberties that other European countries find hard to understand.
The British government has resisted calls to change that practice. Instead it introduced a bill to Parliament this week that would allow the government to issue "control orders," which would ban terror suspects from using the Internet or telephone, and restrict their movements through electronic tagging or house arrest.
There's pressure to act because the current antiterror law expires on Sunday, but the House of Lords has forced Prime Minister Tony Blair to amend the bill by giving judges, not the government, authority to approve control orders.
The bitter row in Britain, says Professor Bobbitt, illustrates his point. "Law- based democracy is clumsy, it is slow, and it is awkward," he says. "But you get something reasonable in the end."