When the US Supreme Court ruled on Thursday that Salim Hamdan, Osama bin Laden’s former driver and an alleged terrorist, could not be tried before a special commission set up at the US military prison in Guantánamo Bay, Cuba, American newspapers described the rebuke to George W. Bush as “sweeping” and “stunning”. Observers abroad, particularly in Europe, giddily suggested that Guantánamo had been discredited. In the drama of the moment, it was easy to lose sight of the court’s insistence that the case neither questioned nor even addressed the US government’s power to detain Mr Hamdan “for the duration of active hostilities”. Since Guantánamo does not agitate US public opinion in the way that overseas sceptics of the war on terror would assume, the five-to-three decision will wreak no sea change in politics, nor harm Mr Bush. As November elections heave into view, it could just as easily help him.

There were three rationales for the decision – and all were necessary in order to reach it. The first – that of John Paul Stevens, the court’s most leftwing justice – is that the tribunals are unconstitutional because of the nature of Guantánamo. These passages excited human rights activists, but Mr Stevens’s language was measured and left open the possibility of finding another way to prosecute those imprisoned. Then, Justice Anthony Kennedy sought more assurance that the Guantánamo commissions were militarily necessary. Finally, Justice Stephen Breyer held that the system of military commissions was indeed unconstitutional, but primarily because Mr Bush had not consulted Congress first. This is a separation-of-powers argument rather than a human rights one. Mr Breyer noted that: “Nothing prevents the president from returning to Congress to seek the authority he believes necessary.”