Americans are somewhat unique in their belief that it is possible to construct virtuous politicians and insert them into a system that encourages systemic corruption. We attempt to change the human to fit the system, rather than change the system to fit human nature.
Government by it’s nature, because it is a monopoly, and concentrates capital, draws corruption. In the USA, corruption tends to be systemic rather than individual. Meaning that the system encourages politicians to work for special interests, and government workers to collect extraordinary benefits – on avearage have retirement benefits equivalent to something like 750K in savings, compared to 50K for the average citizen — plus they cannot be fired and unlike the rest of us are insulated from market pressures. Monetary corruption, meaning, the privatization of public funds or goods, in exchange for favors, is actually amazingly rare in the USA. Almost all of it is systemic.