It has a sort of coolness to it. "And now, children, you are going to stop fighting. You will each sit in your corner, and you'll be quiet and behaved." That attitude is ruthless, but in the context, it can be understood, and even defended.
Imagine it. Terrible global warfare, and then one organisation takes control of all the nukes, puts them on dozens of Damocles space stations, and promises that if anyone ever invades the neigbours again, the offender gets nuked back into the stone age. Peace, love and understanding... or else. It would even work, probably. Until someone unpleasant gains control of the organisation that has all this immense power. Or until the world decides it would prefer to be free from that "Big Brother". That last scenario has the most potential for interesting ethical considerations. Is it right to keep the peace by force? Or must the peoples be left free to decide their own fate, even if it may well mean a return to the old wars? Is it even acceptable to use nuclear annihilation as a pressure tool? After all, it may stop 99% of all conflicts, but what about that one mad warlord? Can it be 'right' to drop nukes on his people because he is a cruel lunatic?
...is this organisation a force for good, or is it automatically an evil thing, despite its best intentions?
(To be honest, bringing this back to the idea of Lex Luthor: I've always been a big fan of the stories that explored him as a more complex character than just a cardboard villain. In fact, I imagine Lex Luthor would be opposed to this kind of thing. His whole argument against Superman - in the best stories - is that Superman is basically a god, beyond all control, who is inherently dangerous to humans. To Lex Luthor, Superman must be destoyed so mankind can be free and safe from his boundless powers. In this analogy, the nukes in space are Superman, and Lex Luthor is the defender of national self-determination who wants those nukes plunged into the sun or something. With the implication that nationalism has its own evils, and that Lex Luthor may secretly be motivated by less noble motives, such as extreme nationalism...)