constitution or leader

Does the constitution dictate the right or wrong actions of a nation, or does the leader of the nation. I'm sure it is a combination of both plus a host of other factors. Could a dictatorship be well run and just for all under a good leader?

Out of interest and perhaps along a more scientific approach to the question, we could look at real world leaders and their contributions to the world and compare those with their religious/non-religious background as well as the form of government that they operated under.

I will organize the results into a table. Any leader whose religious/non-religious beliefs are in question will be excluded.

A dictatorship can be well run, but only for brief periods or for small populations. Otherwise things get too complex. Nations have been able to look back on their history and see both great kings and tyrants. Unfortunately, such a system is notoriously unpredictable.

The constitution establishes a range, within which the king or president can operate. It establishes limits. One cannot predict exactly what sorts of presidents we will have over the ages or what crises they will have to deal with, but we can define a range of limits to constrain them to a degree necessary. Without established limits, leaders become like untrained dogs who have never had owners to establish their limits of behavior.

The leader is the driver. The constitution is the engine. The parameters of the latter define the limits of the former. But the ability of the former will still matter.