I guess you could file this under the “fish rots from the head” meme.
Human beings tend toward self interest, and this also applies to human beings in government whose job it is to check the self interest of others. This is the basis of a school of thought called “public choice theory“, that is discussed at great length on the latest addition to the blogroll, Unlearning Economics.
Public choice theory doesn’t explain everything. But it certainly explains this, as well as the obvious problem posed by Washington’s revolving door, which has become a perpetual motion machine.
Matt Taibbi has chronicled many anecdotes pointing to the same thing.
One year recusal “regulations” are a joke, frankly. This is corruption far too fundamental and astounding to be addressed by a glorified cooling off period.