IANAL, but I feel pretty confident that you are egregiously misrepresenting that ruling. When you say "works can be retrieved into private possession," that makes it sound like you can pick out a public-domain work and claim it for your own, which is not at all a fair summary of what the court said. It's like hearing that locking somebody up without food or water counts as torture and false imprisonment, and then proceeding to tell everyone, "It's an open question whether you can legally refuse to give someone your food when he asks." I do not believe the question is all that open.
As anybody who takes the time to read the ruling will see, the Supreme Court ruled that Congress has the power to make laws that retroactively extend the copyright of certain works that had fallen into the public domain, and specifically said that Congress was empowered to do so if a treaty required it. I do think it's a bad ruling, but it is a far cry from a private party being able to swoop in and snatch works out of the public domain.
As anybody who takes the time to read the ruling will see, the Supreme Court ruled that Congress has the power to make laws that retroactively extend the copyright of certain works that had fallen into the public domain, and specifically said that Congress was empowered to do so if a treaty required it. I do think it's a bad ruling, but it is a far cry from a private party being able to swoop in and snatch works out of the public domain.