We need to fight smarter against jihadism. When Muslim youths in Britain start choosing to become suicide bombers, we are clearly losing the hearts-and-minds struggle. Better intelligence and police work can bring us only part way to a more secure world. We have to deal with symbols: The United States must shut down the Guantanamo prison camp.

Locking detainees up forever is impractical in a war of ideas, and at home and abroad, even within the Bush administration, there is growing unease about Guantanamo. It could probably be closed tomorrow if Washington could agree on what to do with about 520 mid- to low-level Taliban and al-Qaida suspects there. (The top-tier catches are not at Guantanamo, having long since been sequestered by the CIA at as-yet-undisclosed locations.)

Sometimes history can help. In 1945, Britain, the United States and France created an international system to monitor Nazis considered most likely to commit acts of terrorism against the liberating armies, and ultimately watched them until their deaths. The allies built a vast evolving database – identities, fingerprints, biographies – and then pooled their police, military and intelligence resources.

Today, the database could be much more complete. Detainees should have their irises scanned, their voices imprinted and their faces measured, and this biometric data, along with the rest of their files, should be lodged in a central international agency to which all our allies in the war on al-Qaida – from Canada to Spain to Indonesia – would have complete access.

Most of the detainees could be returned to their home countries, where they could be prosecuted and jailed. Some may well end up incarcerated for a very long time; others would be released, but they would be subject to monitoring by the allied counterterrorism center for the rest of their lives.

Of course, there are risks with such a strategy. The first is that even small fry may make trouble again. But because successful and sustainable counterterrorism will never create 100 percent security – an impossibility – the answer is in ever-improving security systems, the vigilant management of acceptable risks.

Another risk is intelligence leaks in such a large, multinational monitoring system. In the 1940s, the British recognized that to beat Hitler they had no choice but to share information with Washington, which had a notoriously porous intelligence system. We similarly don’t have a choice now. The cost of breaches from jihadists at the lower levels of, say, the Saudi and Pakistani intelligence services would be offset by the huge and immediate propaganda benefit of closing Guantanamo and the long-term value of arming Saudi, Pakistani, Malaysian and Indonesian immigration, customs and intelligence officials with more counterterrorism information.

Ultimately, releasing the Guantanamo prisoners could also offer intelligence benefits. Some of these individuals may attempt to rejoin old networks, thus revealing them.

Moreover, if we handle the releases carefully, we could confuse the Taliban and al-Qaida about whether detainees were recruited by us to be double agents. In the late 1980s and early 1990s, an alliance of the CIA, the Israelis, the Jordanians and the PLO destroyed the Abu Nidal faction through this kind of psychological warfare.

The closure of Guantanamo might provide the cornerstone for a renewed allied effort against jihadism. It would certainly help the Bush administration regain the high ground in a fight in which we should be the good guys.