For there to be a paradox, the observers would have to find out about it sooner than it would take light to communicate the result. Otherwise, the earliest tim

For there to be a paradox, the observers would have to find out about it sooner than it would take light to communicate the result. Otherwise, the earliest time that the aliens can find out if they're going to invade or not is when they make the decision. Sure, the observers can find out, and try to tell each other and the aliens, but since it takes at least a round trip of light from the aliens to the observers, the observers always find out after the aliens have made up their minds. If the aliens find out that they make the decision when they make the decision, it seems to me at least that they actually made the decision rather than having it be predestined