Subsidiarity.<p>Subdsidiarity is the principle that decisions should be made locally as much as possible. In government it's what we call "federalism": most decisions are made by individuals; those that cannot are made by local government answerable to the people; those that cannot be made locally may be made by the county or state; only those very few decisions that cannot be made by states are the purview of the federal government. The US was supposed to operate this way. It hasn't since before World War I.<p>Why is subsidiarity connected to rational decision making? Simply, because the world is too complex for any one person or group to understand, model, predict, and control it. Most decisions can be made best by the individuals concerned, who have the relevant knowledge. This also reduces the cognitive burden on everyone else. Since higher authorities have few powers, their impacts are minimal. Citizens who do not have the time or information to follow those high level decisions may <i>rationally</i> ignore and trust the system, because it has little impact on them. Those who do have the inclination to pay attention to politics can make a fair evaluation of their leaders because the leaders are only involved in a few things.<p>One of the reasons you see people acting in such an emotional and heuristic way, nowadays, is that the central governments and even transnational organizations are at the same time manifestly incompetent and incredibly impactful. All citizens <i>must</i> be concerned with who wins the federal offices, because the federal government seizes half of every dollar they earn, and imposes itself into every intimate choice they make. So no one can afford to ignore it. At the same time, government is so complex and makes so many decisions that no citizen has the time or information to study it thoroughly. So what can a rational person do? They must seek shortcuts, such as finding trusted personalities to follow, or making judgments based on rules of thumb, slogans, and so forth.<p>In sum, because rational choice is only possible when we have the time and the information needed to make choices, neither the citizen nor the central authority can make rational choices in a centralized superstate. Decentralizing decision making spreads the work out to more minds, and places less burden on each individual.