Singly, most likely. If we are held accountable by our beliefs, like the three branches of split power of the US government was supposed to do, it is much harder to corrupt the state, even with all that power.
If you have good intentions in the beginning and predict your greed, you may as well prevent yourself from causing harm, though preparation enough would have to be long-term, and that doesn't mean that someone else might come along and continue to corrupt your anti-corrupt measures.
This raises an interesting idea. Does power really corrupt? Or does power just facilitate the fulfillment of our inborn egotistical tendencies?
Probably more of the latter. Power is a catalyst of our corruption, though in itself stems from ourselves.
Considering, though, was this corruption wholly within us the entire time? Are poor people justified in their desire for more money, but rich people greedy when they ask for more when they have more than someone else? Some people are simply unhappy no matter how much they have - they just want more. More power just presents the means to do more, and thus corrupt more.