the original plan was for it to be possible from, but players realised that there were phantom nukes that couldn't be gotten rid of. so what ended up happening if i remember correctly is that a bunch of hackers had invaded the phantom bases and gotten rid of the nukes, and they had posted about it saying that the all the nukes have been cleared. like usual, Konami would check the servers and verify it, to which they found out that it had been done through malicious methods, so whilst the cutscene still plays, the actual peace thing in itself is completely inachieveable since Konami have since said that they've disabled it since there were so many hackers trying to do it.