* Although Justice John Paul Stevens wrote the court's primary opinion, Justice Anthony Kennedy decided the case. Kennedy joined Stevens and the three other "liberal" justices in some aspects of the case, yielding a 5-3 majority, but declined to join others, producing an inconclusive result on those issues.
If the Supreme Court breaks 4-4 on a case, or on an issue within a case, the lower court ruling is "affirmed by an equally divided court," as we say in the legal research biz.
(Because Chief Justice John Roberts joined the lower-court decision the Supreme Court was overturning, he did not participate in today's ruling but can be assumed to agree with the three dissenters.)

* The Kennedy majority agreed that the Detainee Treatment Act of 2005, which grants the U.S. Court of Appeals for the District of Columbia sole jurisdiction over habeas corpus petitions filed by Guantanamo detainees, does not strip the Supreme Court of jurisdiction in this case, because Hamdan had already filed for the writ when Congress passed the act.

* The Kennedy majority held that the military commission the Pentagon set up to try Hamdan was not authorized by the Uniform Code of Military Justice.

* The Stevens plurality wanted to go further and hold that Common Article 3 of the Geneva Conventions--which provides that war crimes trials be conducted by "a regularly constituted court"--requires that Hamdan be present at his trial, even if sensitive intelligence is being aired. But Kennedy thought it unnecessary to reach a conclusion on this question.
That means that the lower court's holding on that point is affirmed.

* The Stevens plurality also wanted to declare the charge against Hamdan--conspiracy--invalid under international law. Kennedy again saw no reason to reach the question.
Ditto.

We have assumed . . . 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.