SO MUCH changed after 11 September 2001. The terrorist attacks on the US had such profound global consequences that they have lodged in the world's collective imagination as a pivotal moment in history. That makes it hard sometimes to see them, in the plainest of terms, as a crime.
But the need to see 9/11 in precisely those terms is implied by last week's decision by US authorities to try Khalid Sheikh Mohammed, the self-confessed mastermind of the attacks, and four alleged accomplices, in a civil court in New York. It is a decision for which President Barack Obama deserves great credit.
The men have been held in Camp Delta, the US military detention centre at Guantánamo Bay. Its closure was an important election pledge for Mr Obama, signalling an intent to reassert the primacy of constitutional law in the conduct of America's anti-terror policies. Khalid Sheik Mohammed's arrival on US soil, and entry into a court room under US legal jurisdiction, will be a moment of great symbolic importance in that process.
Under President Bush, US and international statutes governing the rights of prisoners – civil or military – were subordinated to expediency in the pursuit and interrogation of terrorist suspects. The White House condoned kidnap, indefinite detention and torture as part of a "war on terror". That apparatus did much to corrode the image of the US as a bastion of fairness, governed by constitutional principle. That image would have been sabotaged further had all terror suspects been tried, as was Mr Bush's intention, in secret military tribunals. Justice would be neither seen nor done.
That is not to say that a trial of the alleged 9/11 plotters in a federal court will signal a perfect constitutional restoration, nor that past aberrations are easily forgotten.
There is no clean break from the Bush approach. Khalid Sheik Mohammed was detained for years without charge and subjected to "waterboarding" – now admitted by the US to be a torture technique – some 183 times. Evidence thus procured will be tainted. That legacy will be on trial alongside the defendants. Lawyers will find much to debate even before testimony is heard.
Then there is the problem of disinterested jurors. There is hardly a chance of finding 12 Manhattan residents who have not already formed strong opinions about the crime and the defendants. The whole nation saw itself, in some sense, as a victim of the 9/11 attacks. Victims must be served by justice, but do not usually sit on the jury that provides it.
Meanwhile, the trial will become a global media spectacle. What happens inside the courtroom could be an advertisement for US justice, but the circus all around it will provide countless opportunities for fiery partisan point-scoring. Too much political show business could create a show trial.
Finally, there is the problem of the death penalty, the US attorney general's preferred outcome. Opponents of capital punishment have been quick to point out the inconsistency of holding a civil trial on grounds of juridical principle, only to haul the accused from the stand and kill him in cold blood, albeit with state authority.
It is safe to say that most observers of this process, abroad and in the US, of all political stripes, will find cause to be dissatisfied. It will be a complex process and there will be unforeseen consequences. Some defendants could be acquitted.
But that is the point. A fair trial does not have a fixed outcome. That is what President Bush failed to grasp. He was wedded to an anti-terror strategy that believed the ends of a more secure America justified any means. But that is revolutionary justice – confusing the will and power to enforce an outcome with the moral right to do so at any cost. It is the intellectual basis for tyranny.
Mr Obama has chosen a different, harder path: democratic justice. It is imperfect, but it is always better.