Lord Acton famously wrote that "power tends to corrupt, and absolute power corrupts absolutely," a statement frequently quoted and all too often accepted at face value. I like Mark Earley's clarification:
But remember this: power corrupts, but power itself is not necessarily corrupt. God has given power to the state to be used to restrain evil and maintain order. It is the use of power, whether for personal gain or for the state’s ordained function, that is really at issue.
I would expand on this, because it has relevance beyond political life. All of us, as God's image-bearers, are gifted with various capacities (i.e., power) enabling us to fulfil the responsibilities of the authoritative offices in which God has placed us. These capacities are not in themselves corrupting. However, like everything else in God's good creation, they are capable of being misused by sinful human beings. It's not the power as such that corrupts; it's our own rebellious nature that does so. Acton's saying might be closer to the truth if turned around: Human sin corrupts the otherwise legitimate use of power.