Compared to many places on Earth, corruption in the U.S. is tame. This does not absolve the thieves on K-Street or in Congress or in a thousand other places.
But perhaps the worst corruption involves liberal politicians and schools; their obeisance to the education establishment (lobby) condemns the poorest to the worst schools. The costs (human, fiscal, economic, you name it) are staggering.
In today's NY Times, John Tierney (requires TimeSelect) writes:
"Democrats once went to court to desegregate schools. But in Florida they've been fighting to kick black students out of integrated schools, and they've succeeded, thanks to the Democratic majority on the State Supreme Court.
"The court's decision on Thursday was a legally incoherent but politically creative solution to a delicate problem. Ever since Florida's pioneering statewide voucher program began, Democrats have been struggling to deal with the program's success."
The complete article is worth reading. Those who are the most shrill (and sanctimonious) when advocating "social justice", "the children", "people of color", "equity", etc. work the hardest against their causes (slogans, actually).
They do anything they can to protect a favored constituency. That's corruption.