Clinton himself had to be elected to high office, because if he had been nominated to, say, a cabinet position he could never have been confirmed. His ill-concealed shady personal history would have forced the withdrawal of his nomination. After a few days of lurid headlines, he would have been forgotten. But having achieved the presidency, he was able to surround himself with layers of people, in the executive branch and in the news media, who were willing to overlook, or help conceal, everything. His final mistake was to embarrass them when they no longer needed him.
Corruption takes countless forms.
By its very nature its extent is impossible to calculate. We can never know who really rules those who rule us. The vulnerability of the individual is another reason for not investing too much power in any single government official. The same is true of bribery. It creates a secret relation between a government official and a private interest.