Hostage or prisoner, it's certainly something like that. But it looks like Israel is doing this more or less on its own. The U.S. is acquiescing in it (and maybe even approves privately), but that's all. (Or maybe this really is the preferred policy of the U.S. at this point, as you seem to be thinking. It's hard to tell. I'm just surprised that it's taken Israel this long, when you think about what they've been living with lately.)