This poem came out of the July 3, 2012 Poetry Fishbowl.  It was inspired by a prompt from rowyn.  It was sponsored by Anthony & Shirley Barrette.

Humanity discovered that
the optimum size of a civilization
was the city-state.

It was large enough to hold
a goodly supply of resources,
yet still small enough that
people could get to know
most of the folks in their field.

That made it possible to elect leaders
who actually knew what they were doing
most of the time, in most places,
if that was what people wanted to do.

They learned to trade in networks,
from city-state to city-state, following
the slow change of terrain and goods.

The borders were softer and smaller,
bumping and nudging against each other
like horses milling in a familiar herd,
here and there firmed up
by the line of a large swift river
or a shift from one language to the next.

The city-states might quarrel, now and then,
over this valley or that mine,
driven to conflict by a drought or
somebody obsessed with saber-rattling.

Yet on the whole they were peaceable,
for they never developed that drive of dominionism;
they did not long to subjugate and absorb each other,
growth as unlimited as cancer until the body's bounds.

So it was that humanity
spread across the globe like a net,
each city-state a little knot of culture
connecting to many others
by the long fine lines of alliance.