Not that this made it any easier for the US to decide between the various ways of dealing with terrorists. Last September, for example, a CIA-controlled drone above Yemen killed Anwar al-Awlaki, a US citizen who was then al-Qaeda's most effective propagandist. Another American jihadist, Samir Khan, was killed in the same attack.

Was this any less lawful than the attack by US Special Forces last May on a compound in Pakistan during which they shot dead Osama bin Laden? In theory, he could have surrendered, not a privilege available to someone targeted by a Hellfire missile.

Realistically, there is little chance of surrender to US Special Forces who know that they have, according to Shawcross, just one-tenth of a second to pre-empt a suicide bomber. The US argues that any terrorist could hand himself in at any time.

According to the State Department's legal adviser, Harold Koh, it was certainly legal to kill the al-Qaeda leader. Bin Laden was the leader of an enemy force which posed an imminent threat to the US. And the same went for al-Awlaki. The jihadist must have known that the US regarded him as covered by the president's authorisation for the military use of force, which a joint resolution of Congress approved immediately after the attacks of September 11, 2001.

Of course, there is another way of dealing with alleged terrorists and the Americans are struggling with that too. In 2009, the US Attorney General Eric Holder announced that Khalid Sheikh Mohammed, who had been captured in 2003, would be flown from Guantánamo Bay to be tried at the federal courthouse in New York, just a few blocks away from where the Twin Towers had stood. Some 18 months later, though, Obama announced that the alleged architect of the 9/11 attacks would be tried in a military court after all.

Which brings us back to Nuremberg, where it proved possible to complete the main trials little more than a year after the war's end. War or no war, I regard it as legitimate for a state to kill those who would otherwise kill its citizens if those killers cannot be safely captured. Better still, states should arrest and try them. And I'm less worried by whether it's a military or civilian court, so long as they get on with it.