The Supreme Court ruling in the case of Hamdan v Donald Rumsfeld, Secretary of Defense, et al., on 29 June 2006 did far more than settle the limited question of whether alleged terrorist detainees can be tried before secret military tribunals. By declaring Bush's position unconstitutional, the court in effect judged his concept of his presidency and his methods in his "global war on terror" illegitimate. In his majority opinion, Justice John Paul Stevens's strategic capitalisation emphasised the larger point: "The Executive", he wrote, "is bound to comply with the Rule of Law."

The high-court's decision threw the Bush administration's policy on detainees and its central legal tenet on the presidency into chaos. President Bush had declared he was awaiting the ruling in order to determine what he might do about prisoners held at Guantànamo. But the president's press secretary Tony Snow explained that nothing had changed: "It's not really a reversal of policy", he said.

That same day, 11 July, deputy secretary of defence Gordon England issued a memo ordering that as a result of the Supreme Court decision, the United States armed forces would adhere to the Geneva conventions, which Bush had unilaterally abrogated in a 2002 executive order. "You will ensure that all (department of defence) personnel adhere to these standards", wrote England, who insisted that the administration was already in compliance with a policy it had opposed.

At the moment England's memo was reported, the Senate judiciary committee was hearing testimony from Bush administration officials. "Surprising and disappointing ... without historical analogue", said Stephen Bradbury, the acting assistant attorney-general, about the ruling. Nonetheless, he reluctantly conceded that the administration would adhere to it, though he did not specify what changes would be made and said, contrary to the court and the constitution, that the president does not require congressional approval and can decide what he chooses on his own.

Inside the Bush administration, senior legal authorities refer to their novel framing of the law as the "war paradigm." Its origins can be traced to vice-president Dick Cheney's experience with the thwarting of Richard Nixon's imperial presidency and Cheney's subsequent decades-long effort to recreate it on a new basis. The attacks of 11 September provided the casus belli for the concentration of power in an executive unfettered by checks and balances. Legal doctrines developed by neoconservative theorists, who happened to be appointed to key posts in the justice department's office of legal counsel (OLC) were applied.

Sidney Blumenthal is a former assistant and senior adviser to President Clinton. He is the author of The Clinton Wars (Farrar, Straus & Giroux, 2003) and writes a column for Salon and the Guardian.

Also by Sidney Blumenthal in openDemocracy:

"Bush's Potemkin village presidency"
(September 2005)

"Republican tremors" (October 2005)

"George W Bush: home alone" (October 2005)

"Dick Cheney's day of reckoning"
(November 2005)

"Dick Cheney's shadow play" (November 2005)

"Condoleezza Rice's troubling journey" (December 2005)

"Bush's surveillance network"
(December 2005)

"Bush's shadow government exposed" (January 2006)

"The Republican system" (January 2006)

"George W Bush: running on empty" (February 2006)

"The rules of the game" (February 2006)

" The imprisoned president"(March 2006)

"Bush's world of delusion" (March 2006)

"Bush's truth"
(April 2006)

"The secret passion of George W Bush"
(May 2006)

"The ruin of the CIA" (May 2005)

"The president of dreams" (May 2006)

"The Bush way of war" (June 2006)

Instantly, the war paradigm became operational. Cheney and his then-legal counsel and current chief-of-staff David Addington, directed John Yoo, deputy assistant-director in the OLC, to write the key memos detailing the new imperial presidency. The first principle is that president as commander-in-chief can set or obey laws as he wishes. From that flowed Bush's dismissal of the Geneva conventions, denigrated as "quaint" by then-White House legal counsel Alberto Gonzales, now US attorney-general.

On 2 February 2002, Bush signed a directive unilaterally withdrawing enforcement of the Geneva conventions, specifically common Article 3, which prohibits torture. He has also: evaded the foreign intelligence surveillance court (FISC), ordering the national security agency (NSA) to engage in warrantless eavesdropping on Americans; invested his vice president with presidential powers over classified intelligence; and imprisoned thousands of alleged terrorists without due process of law.

The political dimension of the war paradigm is inextricably linked to its legal one. It has the advantage of serving a polarising politics. "Either you are with us or you are with the terrorists", Bush said repeatedly after 9/11. Against the war paradigm Bush's warriors propped up a straw man they call the "law-enforcement paradigm". The efficacy of law enforcement or the ineffectiveness of waging "war" is beside the point. Those for "war" are true patriots and strong, but those for "law enforcement" are weak and wimpy. "One is sort of a crime-solving approach, a law-enforcement approach, and the other is a national strategy, military, intelligence, wartime approach", Cheney said.

But even more than Cheney, Karl Rove, Bush's chief political advisor, has been the public advocate of the war paradigm as a political wedge issue. Speaking before the Conservative Party of New York state in 2005, Rove said, ''Perhaps the most important difference between conservatives and liberals can be found in the area of national security. Conservatives saw the savagery of 9/11 and the attacks and prepared for war; liberals saw the savagery of the 9/11 attacks and wanted to prepare indictments and offer therapy and understanding for our attackers." In the demonised politics and legal netherworld of the war paradigm, the rule of law is for sissies.

A question of authorisation

And yet Hamdan's case moved through the courts. Salim Ahmed Hamdan, believed to be a driver and bodyguard of Osama bin Laden, was captured in Afghanistan in 2001 and jailed at the Guantánamo prison camp. The Bush administration held him for a year without charges and then declared he would be tried at some unspecified time before a secret military commission on unspecified crimes of "conspiracy". In this kangaroo court, Hamdan was not entitled to be present, or to see or learn any accusations or evidence against him. Hearsay would be admissible, though he'd never know what it might be. So Hamdan filed a suit challenging the legality of the tribunal and claiming he had rights under military and international law.

Now the Supreme Court's decision has thrown Bush's war paradigm into profound crisis. As the Republicans nervously approach mid-term elections in November 2006, Rove's first reaction was to prompt the Republican Congress to uphold the discredited policy in order to continue demonising Democrats. But transforming the issue into another Manichaean battle of "us" versus "the terrorists" did not make his position any more constitutional.

"We conclude", reads the court's opinion, "that the military commission convened to try Hamdan lacks power to proceed because its structure and procedures violate both the UCMJ [Uniform Code of Military Justice] and the Geneva Conventions."

The ruling is sweeping in its rejection of Bush's claims; it leaves none of the precepts of his war paradigm standing. In its wake his imperial presidency, at least before the majesty of the law, is a ruin.

Bush's insistence that the congressional authorisation for the use of military force is the basis of his authority as commander-in-chief to assume bottomless extraordinary powers is dismissed. In the Hamdan case, his use of the congressional authorisation to justify military commissions is discarded. But Bush has also cited the authorisation for many of his dubious actions, from holding detainees without due process to domestic spying. The court's opinion is that the authorization cannot serve to "expand or alter the authorization" that Congress initially intended. The president's war powers, the court reminds him, does not contravene the Congress' war powers.

Nor does the president's fiat override the uniform code of military justice (UCMJ) or the Geneva conventions. In the case of the UCMJ, according to the court, the president cannot suppress due process. In the case of the Geneva conventions, he cannot withdraw from an international treaty of which the United States is a signatory. Justice Stevens, writing for the majority, said: "The UCMJ conditions the President's use of military commissions on compliance not only with the American common law of war, but also with the rest of the UCMJ itself, insofar as applicable, and with the 'rules and precepts of the law of nations'."

Bush's designation of Hamdan and other detainees as "enemy combatants", a vague category of stateless persons not granted the international protections of prisoners of war, is tossed out. Stevens cites common Article 3 of the Geneva conventions, but without elaborating its substance. That article, in fact, forbids torture – "cruel treatment and torture [and] outrages upon personal dignity, in particular humiliating and degrading treatment". Here, therefore, the court rejects Bush's torture policy. (And, as we shall see, Anthony Kennedy raises common Article 3 with possibly explosive consequences.)

Whether Hamdan is associated with a power that signed or didn't sign the Geneva conventions is irrelevant, despite Bush's argument that the issue is central. "Common Article 3, then, is applicable here" and, Stevens goes on, citing the court's collective opinion, "requires that Hamdan be tried by a 'regularly constituted court affording all the judicial guarantees which are recognized as indispensable by civilized peoples.'"

Stevens's conclusion does not show any sympathy for Hamdan, or suggest that he has been unjustly imprisoned, or that he should be released. Contrary to Rove's earlier insinuations, he does not offer "therapy" or "understanding". Stevens, however, does wear his heart on his sleeve on "law enforcement".

"We have assumed, as we must, that the allegations made in the Government's charge against Hamdan are true", he writes. "We have assumed, moreover, the truth of the message implicit in that charge – viz., that Hamdan is a dangerous individual whose beliefs, if acted upon, would cause great harm and even death to innocent civilians, and who would act upon those beliefs if given the opportunity. It bears emphasizing that Hamdan does not challenge, and we do not today address, the Government's power to detain him for the duration of active hostilities in order to prevent such harm. But in undertaking to try Hamdan and subject him to criminal punishment, the Executive is bound to comply with the Rule of Law that prevails in this jurisdiction."

Justices Stephen Breyer and Anthony Kennedy added to the impact of Stevens's opinion with important concurrences. Breyer underlined the point that the congressional authorisation cannot be used by Bush to rationalise whatever action he chooses. "The Court's conclusion", he writes, "ultimately rests upon a single ground: Congress has not issued the Executive a 'blank check'."

Breyer's citation of the phrase "blank check" is his way of evoking the justice who has just retired, Sandra Day O'Connor, and her opinion in Hamdi v Rumsfeld, a case in 2004 that foreshadowed the Hamdan decision. The court ruled in that case that a US citizen, held as an "enemy combatant" in Guantánamo, could not be detained indefinitely without the right to challenge his imprisonment and the right to counsel. O'Connor wrote, "A state of war is not a blank check for the President."

A question of prosecution

When O'Connor was on the court, she was considered to be the key swing vote. Now that pivotal spot belongs to Anthony Kennedy. His opinion is worthy of intense interest, however, for more than that reason. Kennedy ventures into territory where others have not. His disdain for Bush's position is palpable.

He cites Justice Robert Jackson's famous opinion in the 1952 Youngstown case: "When the President takes measures incompatible with the expressed or implied will of Congress, his power is at its lowest ebb." But Kennedy quotes Jackson not simply to expose the depth to which Bush has sunk. He is building toward another conclusion – those who violate the Geneva conventions can be prosecuted for war crimes.

The Geneva Conventions, after all, constitute an international treaty, enacted by the Congress. "By Act of Congress, moreover", Kennedy writes, "violations of Common Article 3 are considered 'war crimes,' punishable as federal offenses, when committed by or against United States nationals and military personnel. See 18 U.S.C. §2441. There should be no doubt, then, that Common Article 3 is part of the law of war as that term is used in §821."

Kennedy moves on to discuss why Bush's military commissions do not meet the "general standards" of "civilized peoples". He has left dangling the open question of war crimes. But the opinion of a justice of the Supreme Court speaking in the majority is not merely a theory. Of all the justices, Kennedy, the swing moderate, has raised the most potentially volatile issue.

But Bush, Cheney, Rumsfeld, et al. , need not worry that they will soon find themselves in the dock. There is little chance that the justice department under Gonzales will ever pursue Kennedy's logic, let alone develop a convoluted argument for why it shouldn't apply.

Indeed, Gonzales expressed dismay at the Supreme Court's decision. On cue and on message, he said, "What this decision has done is, it's hampered our ability to move forward with a tool which we had hoped would be available to the president of the United States in dealing with terrorists." Nonetheless, he said that the administration would work with the Republican Congress "to look at legislation" and he was "hopeful that we will have the ability to try people through military commissions."

Within hours of the Supreme Court ruling, House majority leader John Boehner of Ohio circulated a memo, obviously already prepared, among Republican members that provided them with talking-points: the court had given "special privileges to terrorists" and the Democrats were weak on terrorism. "There is a clear choice between Capitol Hill Democrats who celebrate offering special privileges to violent terrorists, and Republicans who want the president to have the necessary tools to prosecute and achieve victory in the global war on terror", the memo stated.

Though the Hamdan decision devastates the legitimacy of Bush's war paradigm, his initial instinct was to rally around it. Those legal minds in the administration behind the memos from which sprang the far-flung system of prisons holding droves of detainees without due process in Iraq and elsewhere – possibly numbering in the tens of thousands, according to Lawrence Wilkerson, a chief-of-staff to former secretary of state Colin Powell – proposed no gesture of transition. Instead, until the Pentagon issued the England memo on 11 July, Rove was given license to react to the court decision as another opportunity for activating the Republican base.

A question of history

Senior leadership in the military has long opposed Bush's war-paradigm policies. From the start the judges' advocate-general vehemently resisted the abrogation of legal standards. Then Powell, the former chairman of the joint chiefs-of-staff, spoke for much of the military in his opposition. But they were ignored. In 2005, the general counsel of the navy, Alberto Mora, and Matthew Waxman, deputy assistant-secretary of defense for detainee policy, strongly argued for adherence to common Article 3. But Cheney, Rumsfeld and Addington suppressed them.

For Rove, Bush's political spearhead, everything is short-term. Nothing matters but the mid-term elections. A new issue that can be twisted to polarise and stir up Republicans is welcomed as a godsend. Through Rove's machinations and a one-party Republican Congress, Bush attempted to create political immunity from constitutional wreckage. Then he was forced to acknowledge the court's judgment. But exactly how he would enforce it remained as murky as ever.

Bush's war paradigm is in a shambles. And the court's decision stands in history. Hamdan is a bookend on the imperial presidency; the decision in United States v Nixon is the other. In his presentation to the Supreme Court, Nixon's attorney, James St Clair, argued: "The President wants me to argue that he is as powerful a monarch as Louis XIV, only four years at a time, and is not subject to the processes of any court in the land except the court of impeachment." On 24 July 1974, Chief Justice Warren Burger, speaking for the court, ruled that there was nothing in the constitution to "sustain an absolute, unqualified Presidential privilege of immunity from judicial process under all circumstances." Nixon was forced to give up his incriminating White House tapes, and he resigned on 9 August. In Nixon's fall began Cheney's dream.

There are many monuments to presidents in Washington, but there is no Nixon memorial, only the Vietnam War memorial. If there is ever a Bush monument, it may be a cage surrounded by barbed wire, above which is engraved in marble the lasting judgment of Justice Stevens: "THE EXECUTIVE IS BOUND TO COMPLY WITH THE RULE OF LAW."