Corruption is a product of inequality of power, not of whether someone is good or bad. If someone accumulates enough power to break the rules, it is almost certain that they will take advantage of such an opportunity.
That extra power can come from centralization of economic power (economic inequality) or political power (authoritarianism-existence of elites). Bureaucracies and elites can act with advantage by access to information denied to the rest of the citizenry.
The best guarantee against this corruption is that there are no such excessive power differences. That is economic equality, transparent, democratic, and horizontal government. In such a context, there would be no one capable of abuse or in the position to avoid punishment.