Panetti v. Quarterman (06-6407)

From the Scotus BLOG :

In a second opinion by Kennedy, also splitting the Court 5-4 but along different ideological lines, the Court ruled that the Fifth Circuit Court had used too restrictive a standard of mental competency in upholding a death sentence for a man whose delusions are said to keep him from fully understanding why he would be executed. The case was Panetti v. Quarterman (06-6407).