On the face of it, the decision is a logical follow up to the Court’s 1997 decisions upholding the right of states to ban assisted suicide. This makes it a victory for states rights. As the late Chief Justice Rehnquist wrote in 1997:
"Throughout the nation, Americans are engaged in an earnest and profound debate about the morality, legality and practicality of physician-assisted suicide. Our holding permits this debate to continue, as it should in an [sic] democratic society"
That two of the Court’s biggest supporters of states’ rights, Scalia and Thomas, dissented is an indicator that the growing division over “gates of life questions” is beginning to overwhelm conservative support for the tenth amendment. Perhaps states' rights are reserved for the righteous.
One more thing, Kennedy’s reasoning, as reported, is pretty narrow. He focused on the narrowness of the category of patients so empowered. He also suggested that it was an overreach for the Attorney General to do this unilaterally. This latter point leaves open the possibility for a different verdict if federal law specifically banned medical assistance in suicide cases.
Added January 18: Here is a link to Gonzales v. Oregon. The opinions begin on page 5.