I am looking for statistics, expert surveys of unquantifiable things are accepted, and they can include whatever you value, but with the essential requirement that they cover many countries and not just the US.
I provided just such a source, you haven't.
You say US elections are corrupted by corporate money. That is true, but what comparison do you have regarding that with the rest of the world? My source rated the US high, but not as high as places like Canada, Germany, and Scandenavia.
You claimed we were the most corrupt country in the world. Hence, you would probably have to be showing us how we fare worse than Zimbabwe, Sudan, Chad, Venezuela, and the like.
I will concede this: the countries Bush had us occupy are about the world's most corrupt. Though, they weren't that far off from being such in the first place.