Hello there.
Louis XVI was forced to accept the national Assembly's decree because thousands of armed parisian woman descended on the palace and captured him and his family.
Answer:
It is a law that the Congress passed in 1850 that stats runaway slaves to return back to their owner.
I would say its because no one really decided to change anything. No one during the old ages really knew how to do anything and only used what they had and what was closest to them.
who ever has it ,they will make different decisions than they would have individually.