Political power can be distributed either top-down or bottom-up, but it can also be limited in various ways. There are a number of ways to limit political power. It may be limited by a higher authority, by a lack of need, by a shared moral system or by a shared agreement. These ways of limiting political power describe all of the possible ways to limit such power.
The first way to limit political power is by a higher authority. This authority, by force, money or social pressure may force a lower tier of government to obey it. This provides no limitation of highest levels of government. It also will use the authority to throttle a lower tier as an occasion to increase its own power. Therefore, this means of limitation is the most ineffective.
The second way to limit political power is by a shared agreement. This is often called the rule of law. This is an agreement to limit power by the constitution (or by some other set of laws). It may even limit power through the use of a contract. This can limit all tiers of government. It has a somewhat well-known weakness though. The interpretation of the law is itself provided by the government. Therefore, if the government desires to have its power increased, it may simply re-interpret these agreements so that they now favor the addition of new powers. This means of limiting power is therefore either temporary or exists only so long as the agreement is understood by a majority of the populace so that the government may not re-interpret it.
The third way to limit power is by a lack of need. This is dependent on the circumstances, but it is extremely effective. If there is something that we do not perceive a lack of, then the government cannot offer to provide it. If there is nothing wrong, then the government cannot offer to fix it. Since both “fixing” and “providing” are means of power, these are limited by lack of need. This applies to all areas of power. This is especially a limitation on smaller governments. A small government is one that a single person can comprehend. So anyone would know if the government wanted to interfere in an area in which there was no need. A large government could interfere and few would even know that the government was doing it! As long as the government is capable of lying about needs, it may interfere with something like that if it is large. Therefore, in a morally lacking society, this is no limitation on large governments.
The fourth and most effective way of limiting government power is by a shared moral system. If the majority of the populace agree on what the governments powers should be then that agreement will be strong enough to bind the government. This is stronger than a mere shared agreement because this agreement is founded morally. It is therefore important to all parties, much more easily transmissible to future generations and violation of it is automatically a moral fault. If a shared moral system binds the government, then this binding will last a long time, apply to all forms of government at all levels and effectively bind individual officials within the government.
In Canada, our government is bound by a shared agreement the constitution that is mostly followed. It is this that distinguishes us from other (elective) dictatorships. Without a shared moral agreement though, this constitution will not last. The rule of law is dependent on a shared moral system.