A small war of words between Lord Acton and Frank Herbert:
“Power tends to corrupt, and absolute power corrupts absolutely. Great men are almost always bad men.” ~Sir John Dalberg-Acton
“All governments suffer a recurring problem: it is not that power corrupts, but that it is magnetic to the corruptible.” ~ Frank Herbert, Dune.
My own take, in brief:
Actually, it is both. Most folks can be corrupted by the ability to exercise power over others. For some, it is after the fact: they seek power because they are corrupt; for others it is a very small step; for still others it is a process that proceeds at snail’s pace, so that the longer they exercise power–even intending that exercise to be for the good of their charges–the more corrupt they become.
A minor example of this is parenthood. A parent exercises just power in raising their children within sensible boundaries so that they can lead (generally) happy, productive, and safe lives (within whatever areas are under their control). That authority/power should phase out as the children achieve maturity. It is when children either eschew the responsibilities of maturity and continue to rely on their parents for support or when parents continue to exert controlling “influence” over their grown children that the process–and the individuals involved–either become corrupt or reveal their corrupt nature.
And so with government: exercising controlling power over a supposedly free people is corrupt and illegitimate. Those who want to be a part of that control are corrupt to begin with. Those who become a part of that process with the goal of ameliorating the effects of such illegitimate power inevitably either become corrupt themselves or are purged by the system.
(Long version: The Revolt of the Masses (Ortega) and Suicide of the West (Burnham), et al)
Shorter version: “For all have sinned and fallen short of the glory of God” and “If we say we have no sin, we are liars and the truth is not in us.”
We are all naturally corrupt. exercising any power over others in any way, shape, fashion or form just offers us–all of us–opportunities to misbehave, opportunities we are apt to seize.