A much more difficult issue to deal with.
Humans are a fractious lot.
The body that enforces those laws, or amends them, etc is a government, we will always have a 'state' even if it is just a few tribal elders sitting around a camp fire. As the 'nation' gets larger, the state just gets further removed from the people that it purports to represent. Then the obvious deficiencies in centralisation just become more evident. Unfortunately there is a lot more money to be creamed off in a large state, than there is in a small one.