The Founding Fathers knew. The Founding Fathers hated government, because they knew that power breeds the love of power. They’d have started another revolution over “Unitary Executive Powers,” over “signing statements,” over warrantless spying.
It’s not that power corrupts. I mean, power does corrupt, but that’s another story. It’s that power loves to keep power, just as wealth loves to keep wealth, just as bureaucracy loves to perpetuate bureaucracy.
Life seeks self-preservation. Not just individual life, but all things about which we might say ‘they take on a life of their own’: Communities, nations, causes, institutions. That which has a life seeks to preserve its own life. That’s the nature of things. Not wrong. Just is.
Institutions are founded for reasons, but soon their raison de etre is the preservation of the institution. This may or may not breed corruption, but the mission is lost. Part of why we stay in bad relationships, or dead-end jobs, or hold on to outmoded notions, is simply the self-sustaining urge we apply to each of these things.
So to be in power is to seek to preserve your own power. And the more power you have, the better able you are to do that, until at last you create tyranny. The Founding Fathers created checks and balances, gave primary power to Congress, designed a government that would kick the President in the ass if he went too far, because they foresaw this. They foresaw that to be powerful is to seek to steal power from others. In a word, they foresaw George W. Bush. That’s why they gave Congress the power to stop him (or at least slow him way down). All Congress has to do is act.