Partisan gerrymandering is wrong, and it is a constitutional wrong, for it involves discriminating against some voters on the basis of their political beliefs and interfering with the process of self-government by the majority. But what is a court to do? An appreciation of the political effects of different districting plans cannot be eradicated from the legislative mind. How much consideration is too much? How is a court to tell? And will the body politic believe that federal judges, because they are unelected, are disinterested referees of the political process?

Until I heard the oral argument, I thought that the Texas case might be the exceptional one in which there was actually a judicially manageable standard that could be invoked to set aside what the state legislature had done. The facts suggest a perfect storm of partisanship: Texas had adopted a Democratically biased congressional redistricting plan in 1990; a split in the control of the state legislature had led to deadlock over the required decennial redistricting in 2001; a court had to act to adopt a plan. Tom DeLay, accusers said, raised illegal corporate money to gain control of both state houses, tried to get the Federal Aviation Authority to monitor Democrats fleeing to Oklahoma to defeat a quorum, and pushed through a partisan plan that made the Texas delegation to Congress heavily Republican.

Finally, it seemed, a case that could be resolved with a "judicially manageable standard." Given the almost unbroken tradition, pegged to the census clause of the Constitution, that the lines for Congressional districts are redrawn every 10 years, some explanation is required for the highly unusual act of the Texas mid-decade gambit. Of the Texas move it can truly be said, to paraphrase the late coach Vince Lombardi, "Partisanship was not the most important thing; it was the only thing."

One sentence leaps out in today's controlling opinion by Justice Kennedy in the Texas redistricting case. He is writing about the decision of the newly installed Republican majority in the Texas state legislature to take the highly unusual step of redistricting the state's U.S. congressional seats in the middle of a decade - specifically, this one. And he says: "The legislature does seem to have decided to redistrict with the sole purpose of achieving a Republican congressional majority, but partisan aims did not guide every line it drew."

I would have thought the first part of that sentence would have disposed of the case: If the legislature has decided to undertake an action "for the sole purpose of achieving a Republican congressional majority," it has right then and there failed the basic constitutional test that all legislative acts must, at the very least, serve some legitimate legislative purpose. An act with the "sole purpose" of achieving a partisan aim does not satisfy that standard.

The decision, five justices - Kennedy, Stevens, Souter, Breyer and Ginsburg - reject the Bush administration's argument that the power to try detainees by military tribunal was implied in the Authorization for Use of Military Force approved by Congress in the days after 9/11.

... the Bush administration has advanced exactly the same argument in support of its warrantless wiretapping program. That is, Attorney General Alberto Gonzales and other administration officials have argued that Congress somehow implicitly authorized the warrantless wiretapping of American citizens when it passed the Authorization for Use of Military Force, or AUMF, in 2001.

So if the AUMF didn't implicitly authorize the use of military tribunals at Guantánamo, it probably didn't authorize the warrantless wiretaps either, right? That's how it seems, but readers with a keen memory will recall that in the Hamdi v. Rumsfeld decision in 2004, five justices - O'Connor, Rehnquist, Kennedy, Breyer and, in a separate opinion, Thomas - reached the conclusion that the AUMF did authorize the detention of enemy combatants for the duration of the conflict in which they were captured. Sandra Day O'Connor wrote then that it is "of no moment" that the AUMF says nothing about detaining enemy combatants. "Because detention to prevent a combatant's return to the battlefield is a fundamental incident of waging war," O'Connor said, "in permitting the use of 'necessary and appropriate force,' Congress has clearly and unmistakably authorized detention in the narrow circumstances considered here.'"

Why is the outcome in Hamdan different?

Assuming a legal challenge ever got to the Supreme Court, the outcome could turn on two questions. First, does the Foreign Intelligence Surveillance Act leave open the possibility that another "Act of Congress" might authorize spying without the warrants FISA requires? Although FISA itself says it's the "exclusive means by which electronic surveillance ... may be conducted," the administration has argued that FISA actually contemplates the possibility that a future act of Congress could expand the president's surveillance authorities. But even assuming the court agreed with that view, it would still have to grapple with the second question: If FISA does contemplate additional, broader authorizations for electronic surveillance, did the AUMF amount to one? To answer that question, the court would have to decide whether spying on American citizens - and, arguably, doing so without a warrant - is such an inherent part of waging war that the power to do so must be read into the AUMF in the same way that the power to detain enemy combatants was.

More importantly, the Court held that Common Article 3 of Geneva applies as a matter of treaty obligation to the conflict against Al Qaeda. That is the HUGE part of today's ruling. The commissions are the least of it. This basically resolves the debate about interrogation techniques, because Common Article 3 provides that detained persons "shall in all circumstances be treated humanely," and that "[t]o this end," certain specified acts "are and shall remain prohibited at any time and in any place whatsoever" - including "cruel treatment and torture," and "outrages upon personal dignity, in particular humiliating and degrading treatment." This standard, not limited to the restrictions of the due process clause, is much more restrictive than even the McCain Amendment.

... This almost certainly means that the CIA's interrogation regime is unlawful, and indeed, that many techniques the administration has been using, such as waterboarding and hypothermia (and others) violate the War Crimes Act (because violations of Common Article 3 are deemed war crimes).

It remains one of the most chilling public statements by a senior Bush administration official. Testifying before the Senate Judiciary Committee in December 2001, Attorney General John Ashcroft blustered, "To those who scare peace-loving people with phantoms of lost liberty, my message is this: Your tactics only aid terrorists - for they erode our national unity and diminish our resolve. They give ammunition to America's enemies and pause to America's friends."

Ashcroft's inflammatory claim that civil libertarians were arming al-Qaida came on a day when the attorney general had the unsavory duty of defending the administration's initial rules covering military tribunals. Now four and a half years later, the Supreme Court's end-of-the-session decision in Hamdan v. Rumsfeld both rejected these military tribunals and quickened the hearts of civil libertarians.

Read narrowly, the court's ruling applies only to the roughly 450 prisoners held at Guant?namo. In fact, Thursday's decision does not even guarantee any kind of trial for these detainees. As Justice Paul Stevens noted in his majority opinion, "Hamdan does not challenge, and we do not today address, the Government's power to detain him for the duration of active hostilities." Yet such a gimlet-eyed interpretation may be the equivalent of believing that Brown v. Board of Education applies only to schools in the greater metroplex of Topeka, Kan.

It is possible that Hamdan may someday be seen as the turning point in repudiating the Bush-Cheney view that all branches of government are equal but some are more equal than others. An optimist could find persuasive evidence in the decision that the Supreme Court was, in effect, saying to the White House: "Enough of your cockamamie theories about the all-powerful president in wartime. Enough of your cloud-cuckoo readings of the resolution that Congress passed after Sept. 11. And enough of your cataclysmic claims that the war against al-Qaida requires a wanton disrespect for international law and the norms of civilized behavior."

... the most compelling passage in Stevens' opinion is this four-word sentence: "That reasoning is erroneous." The octogenarian justice was rejecting the government's cherished argument that not one syllable of the Geneva Conventions applies to alleged al-Qaida captives at Guant?namo. Stevens held that, at minimum, Hamdan and his companions on the American-held tip of Cuba are covered by the portions of the Geneva Conventions that regulate the treatment of prisoners in civil wars and similar conflicts.

I am struggling to feel the same euphoria about the court's repudiation of President Bush's military tribunals in today's rather stunning Hamdan decision.

... If Lederman is right on this, I can take some comfort in an opinion that's about more than just a handful of guys at Guantanamo whose trials are on hold. But for the moment, I am trying to imagine explaining to Mr. Hamdan that the good news today is that he doesn't get a trial at all. The court finds that Hamdan can be detained "for the duration of active hostilities." It's not like the base at Guantanamo has to be closed. This case may not have that much immediate impact, outside of Guantanamo, but as a judicial smoke signal to the president, it's a whopper.

... Today's rebuke to the president still feels hollow to me because I just don't believe the Bush administration cares what the Supreme Court thinks about the constraints on executive war powers. As a legal matter, Bush lawyers always claimed they'd won the last round of enemy combatant cases, even when the rest of us heard O'Connor's admonition, in Hamdi v. Rumsfeld, about a state of war not being a "blank check" for the president. As a practical matter, even if it's true that U.S. forces and interrogators must now abide by the Geneva definition of torture, when is the petition for relief of a tortured detainee going to present itself before this court? And even if Guantanamo is closed, which I gather may soon happen, what is to stop Bush from falling back on secret prisons and extraordinary renditions - which we will never know about?

When I covered oral argument in Hamdan, I marveled at how Solicitor General Paul Clement unfailingly staked out the most extreme legal positions - positions that seemed utterly contemptuous of the court - and then refused to budge from them. He told an astonished Justice David Souter that it was possible for Congress to suspend the writ of habeas corpus accidentally. He told Justice Ruth Bader Ginsburg that enemy combatants simply have no rights under the Constitution and laws of the United States. He just kept repeating the Bush administration mantra: This is war and President Bush is king of the war.

At the time, I wondered how such an unbending, unyielding view of the law, and the world, made any sense. It didn't seem to me a particularly helpful tactic in dealing with a Supreme Court that thrives on nuance. When you're talking to nine people who can churn out 132 pages of painstakingly detailed nuance on a regular basis, does the argument that the president thinks courts are soft, sloppy, and slow really seem like a winner?

... Do the Bush folks take this simplistic view of their own power - throwing around ideas like "unitary executive" and FISA-as-optional - because in the end, they just don't care what the courts think?

The administration isn't really asking for constitutional blank checks. Why should it, when the president thinks he has his own constitutional Swiss bank account?

... Does the president believe he is bound by this decision? Does he refuse to send a really senior representative to a Senate Committee hearing on signing statements; or offer substantive responses to congressional questions about warrantless wiretapping; or offer a nuanced argument to the high court to make clear that he's not accountable to any of those entities? And if the administration refuses to be accountable, then what will today's decision actually achieve? It's all very good for Mr. Hamdan and his nine friends at Guantanamo. But won't it encourage Bush to detain/render/wiretap/torture in even greater secrecy?

Cheer me up, Obi-Wan, you're my only hope.

Because in order to understand the larger significance of today's decision, it is important to be clear about exactly how this presidency departed from fundamental legal principles. The problem is not the president's assertion that he can ignore laws he believes to be unconstitutional. The problem is what laws he believes to be unconstitutional.

For the proposition that the president has the authority to decline to abide by statutes he views as unconstitutional, the administration has relied principally on an opinion I authored as head of the Office of Legal Counsel in 1994. And rightly so. That opinion is based upon long-standing and consistent executive practice. Moreover, the most relevant U.S. Supreme Court decision, Myers v. United States, 272 US 52 (1926), by clear implication considers it appropriate for a president to decline to execute unconstitutional statutes. And as President Carter's Attorney General Ben Civiletti wrote in an 1980 opinion, the president's constitutional duty to execute the laws "does not require him to execute unconstitutional statutes; nor does it require him to execute them provisionally, against the day that they are declared unconstitutional by the courts."

This view is based upon the principle that the president's ultimate obligation is to the Constitution, and if a statute contravenes the Constitution, the president has the authority to decline to enforce it. This applies to laws that unconstitutionally impinge upon the president's own power. It is also unremarkable for a president to announce his view that a provision is unconstitutional in a statement issued when he signs the law.

The problem has been what those presidential signing statements say - even worse, what the legal opinions intended to be secret assert. They claim that laws whose validity has never been seriously questioned are unconstitutional based on extravagant and untenable theories of presidential power.

The fundamental, profound category error made by the administration has been to confuse two utterly different meanings of the term "inherent presidential power." One meaning would refer to what the president has authority to do on his own in the fields of national security and armed conflict when Congress has not acted. That should be a very broad area. The term "inherent presidential power" could also be taken, however, to refer to matters so deeply at the core of presidential authority that that any act of Congress that regulated or limited the exercise of that power would be unconstitutional - even if Congress was acting under legislative powers clearly conferred by the Constitution. That should be an exceedingly small set of matters.

This administration has taken the astounding position that if the president has 'inherent authority' to do an act whenever Congress is silent, then it follows that any act of Congress that regulates such an authority is an invalid impingement on his "inherent power." This conflation of what a president can do if no law prohibits his action and what he can when the law forbids it is a truly insidious legal doctrine.

The court made short work of it today. RIP "inherent presidential authority" to violate valid laws.

This seemingly simply proposition has huge consequences.

... Today's decision has been criticized by conservatives on the court and by some off the court. But just as this is not a victory for terrorists, neither is it a defeat for conservatives, as many will come to realize. Placing the presidency back under the law will look quite different to critics when there is a president less to their liking in the White House.

The Bush administration likely will have to extend rights to terrorism suspects at the U.S. military prison at Guantanamo Bay, Cuba, that it has denied for years, after the Supreme Court invalidated the government's system of military trials and ruled that the detainees must be treated according to international standards, officials and experts said yesterday.

Senior administration officials acknowledged that the ruling scuttles their plans to put as many as 80 detainees through administration-created "military commissions" - with extremely limited rights - and said it is unclear how they will respond. The 5 to 3 ruling in Hamdan v. Rumsfeld sent officials scrambling to evaluate options for the 450 detainees at Guantanamo Bay, some of whom have been held for more than four years without trial.

The choices, experts and government officials said yesterday, largely include putting suspects through time-tested military courts-martial, charging them in U.S. criminal courts or working with Congress to develop new rules to comply with the court's decision.

The administration could also ask foreign governments to try the more than 150 prisoners it considers hard-core terrorism suspects. The rest are likely to be returned to their home countries for further detention or release.

But if the United States decides it wants to hold the trials, detainees probably would gain more access to the evidence against them and the right to be present for much or all of the proceedings - both of which were denied in some circumstances under the military commission rules, the experts and officials said.

The court did not rule on whether Guantanamo Bay should be closed, and its action does not affect operations at the facility. Military officials said yesterday that scheduled military commission hearings for 10 suspects have been suspended.

Retired Army Gen. Barry R. McCaffrey, a professor of international affairs at the U.S. Military Academy who visited Guantanamo Bay last week, said the military commissions were destined to fail. He said the government should have used courts-martial and the Uniform Code of Military Justice (UCMJ), which grants defendants more rights.

"We put ourselves in an unnecessary legal mess from the beginning, and now we've gotten ourselves in such a mess legally and politically, there's no easy solution," McCaffrey said yesterday.