We have often seen how leaders who got into power because of backing from their tribe, sect or regional and ethnicities are the most corrupt ones because they knows that their people will vote for them regardless they do any good work or not. Look at African nations and even some Arab nations the reason why they are going through corruption and suffering is because people don't vote based on merit rather on personal relationship like sect, ethnicity or religion and then there comes countries like India and Pakistan where they win based on vote from majority community by instilling fear that minorities gonna rule them if not votes to power and next five years everyone suffers.
I would hold people accountable for being in an creating a corrupt leaders rather than the leaders themself.
Background One: Many people vote in constituencies for some money. Again when they see that there is no development in the area they say that there is no development in my area, and the leaders loot all the money. At such a time I am talking about all the leaders who came to power in exchange for money will they do the welfare of the people with their own money? Answer: Never.
Background Two: When a government comes to power it wants to stay in power again and again. So when the election comes they don't want to give a chance to the opposite party to participate in the election. But their opportunity to participate is disclosed. Then anyone from among the people of his party is chosen and stood for election. Then what will the general public do and who will vote?
So I think people will be responsible according to the context. But it can be said that the common people cannot escape the responsibility for producing corrupt leaders either through ignorance or purposefully.