Control and Infinity

Walking through the prison, Alec tells Lucky " It's about control..............There are 5000 prisoners here, never more than 200 guards on a shift. They have to be able to lockdown if there's trouble. Divide and conquer. It's the only way to keep order." ( p.5)

Is life really so simple? Can everything be controlled ? Is there a fixed boundary, a number or certain parameters beyond which control becomes impossible? How can this limit be determined?
History throws up numerous examples of a vanquishing power establishing its sovereignty with a policy of divide and rule. But equally, history teaches us that long after the conquering heroes depart, they leave behind a society splintered and filled with hate, deeply divided and distrustful.
So how effective is control in keeping order?