Corruption in this sense of the word is economic and quantifiable, we're not talking about policymaking and who bought off whichever party you hate. The US is near the bottom of the industrialized world in metrics like this.
This is independent of party and more obvious at the local level than national. Look into your local zoning some time.
When the rules says X must be farm land, but changing that so X can become tract housing means local developer can make a few million... Well that's a lot of power to hand some tiny group with minimal oversight. Supplying pencils etc to the local high schools can be a lot simpler if you know the right people...
When the rules says X must be farm land, but changing that so X can become tract housing means local developer can make a few million... Well that's a lot of power to hand some tiny group with minimal oversight. Supplying pencils etc to the local high schools can be a lot simpler if you know the right people...