Probably most folks who follow the Supreme Court or the Texas criminal justice system already know about yesterday's rebuke, but I figured I'd add a few more remarks.
In short, the Supreme Court issued a decision (without oral arguments, and unsigned) that rebuked the Texas high court and sent a death penalty case back to trial on the penalty phase, saying in essence that "We meant what we said, so do it and stop fucking around." The case dates back to a serious (indeed, constitutionally fatal) procedural problem in Texas death penalty cases in the mid-80s. The court is irritated with both the Fifth Circuit and the Texas Court of Criminal Appeals because it has issued clear instructions on how to deal with the procedural problem and doesn't like being ignored.
It's not unusual for the Supreme Court to rebuke a lower court, even a state high court, this way; two or three terms ago, they did exactly the same thing to the South Carolina high court, telling it to follow their instructions concerning a particular penalty-phase problem in death penalty cases.
It is also an example of a gradual swing on the Court back toward defendant-protection. The Burger and early Rehnquist courts swung fairly hard toward curtailing protections for the defendants, upholding, for example, restrictions on habeas corpus appeals and the like, especially in death penalty cases. For the past five or ten years, though, the Court, which performs a delicate balancing act at all times, has been starting to push back the other direction. Lower courts following its earlier lead had begun to limit death penalty appeals to the point of inequity, and the Supreme Court has been stepping back to say, effectively, "We don't mind putting nasty ol' criminals to death, but you've got to do it right, within these narrow parameters." For a man like myself with a Warren-era view of civil rights, this is a welcome change.
If you're interested in learning about the procedural problem--it was a dilly--you can read the opinion here.