The current system is not that bad, a radical shift towards government transparency would help a lot. Make it hard to hide bribery, corruption, and plain evilness, pay well but make it hard to sell favours in the dark. Make it easy for public officers to pay for blatant crimes. Make it hard for a single political group to revert transparency.

Politicians would have more shit to throw around, yes, but hopefully the worst of them will look elsewhere for the easy money if it can't be had that easily in public office.