What exactly does the Guantanamo Detainees case mean?

In Rasul v. Bush today, the Court held that the Guantanamo detainees are entitled to have their detention reviewed, presumably by civilian courts, even though they’re not U.S. citizens, and they’re being held outside the U.S. Johnson v. Eisentrager, a 1950 case involving a similar petition brought by detained Nazi soldiers, seemed to hold the contrary — but the Court distinguished Johnson on four grounds:

1. “[The Guantanamo detainees] are not nationals of countries at war with the United States.” (In Eisentrager, the Court concluded that peace had not been officially declared.)

2. “[T]hey deny that they have engaged in or plotted acts of aggression against the United States.”

3. “[T]hey have never been afforded to any tribunal [even a military one, as in Eisentrager], much less charged with and convicted of wrongdoing.”

4. “[T]hey have been imprisoned in territory over which the United States exercises exclusive jurisdiction and control.”

A big part of the Court’s decision focused on the fourth item — but as Justice Scalia argues, the government’s “exlusive jurisdiction and control” over Guantanamo isn’t really that different from the government’s exclusive jurisdiction and control over occupied Germany. Guantanamo has been controlled by the U.S. longer than German bases were (I suspect that today Germany has more legal authority over U.S. bases in Germany — certainly it has more de facto authority, since if the Germans wanted to kick us out, we’d surely go, whereas we’re not leaving Guantanamo even though Castro does want us out). But it’s hard to see why that should make a difference.

But even if the fourth item is a possible ground for distinguishing Rasul from Eisentrager, the Court doesn’t (unless I’ve missed something) explain whether exclusive jurisdiction and control is necessary for habeas, sufficient for habeas, or particularly important for habeas. What if the detainees had been kept in Afghanistan instead, or at a military base in no-longer-occupied Germany? I don’t see how one can figure out from the Court’s opinion whether they would then be entitled to petition the civilian courts for hearings. And the government does want to know this, since it wants to know where they should be kept.