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.
In almost all countries of the world, political figures are involved in corruption. Everything is done with money, and leaders take advantage of that opportunity. Basically the leader creates a huge network where things like buying votes with money happen. There have also been instances where the common people are disenfranchised, corrupt leaders are elected without a vote by using power. Personally I have seen political figures in the South Asian region, when they hold political power, often build mountains of wealth for personal gain. In many cases, those in power use their influence to protect themselves and their associates from the consequences of their corrupt actions, even as they engage in misappropriation of public funds, bribery, embezzlement and other forms of corruption.
In many cases I cannot blame the people for producing corrupt leaders. Corrupt leaders build powerful terrorist, extortionist organizations to control their areas, and the common people living in those areas live like puppets in their fear.