The colloquial term for this is "revolving door."
- apparent when there isn't (false positive - mistaken)
- apparent when there is (obvious)
- not apparent when there is (false negative - not obvious)
I'd define corruption as a pattern of putting profit/loss considerations ahead of public interests. Other than personal ethics, this is a really hard thing to control for because it goes to why people want to be public servants and what are their interests/relationships.
I could be wrong, but I don't think federal judges and Supreme Court Justices participate in the revolving door. Supreme Court Justices are deeply political, but they're not sell-outs like Chris Dodd.
Corruption can be stopped when voters & consumers have more power than the politicians or their backers. No one can force you to vote a certain way or buy a certain product. You punish "public" "servants" by restricting their power, i.e. voting them out if they break the law or not enforcing the law equally.