If an actual interstellar superluminal civilization wanted to take over the Earth they would simply do so, for we on Earth wouldn't have the power to stop them. Our peace talks and legislation would therefore mean nothing to them. The law of the jungle over rides mans law and moral law since nothing can stop the strongest and most powerful institution from imposing it's will. Rome had vast legions, helmets, armor, and swords made out of steel and titanium going against tribes that used bronze or battleaxes made of stone, funny "coincedence" the most technologically advanced civilizations always seem to impose their will on lesser tribes. Unified China is another example.
In short the Francs and Gauls constitutions and legislations were utterly meaningless to the Romans. Aquaducts and roads are more then a match for unorganized nomadisism of the uncivilized portions of Humanity.
We don't need interstellar constitutions and agreements, we need to develop powerful laser cannons and planetary shields in order to be able to enforce said legislation in the first place to discourage a potential enemy star system from trying to overtake the Earth.
This is a post written by Jay Moody. Thanks