Political liberty—that is, the ability of societies to rule themselves—does not depend only on the degree to which a society can mobilize opposition to centralized power and impse constitutional constraints on the state. It must also have a state that is strong enough to act when action is required. Accountability does not just run in one direction, from the state to society. If the government cannot act cohesively, if there is no broader sense of public purpose, then one will not have laid the balance for true political liberty.
A political system that is all checks and balances is potentially no more successful than one with no checks, because governments periodically need strong and decisive action. The stability of an accountable political system thus rests on a broad balance of power between the state and its underlying society.
From Francis Fukuyama's The Origins of Public Order, p.431