This is a good explanation of the Irish Machine in Chicago, corrupt white governments in the south, and Somalian welfare scams in Minnesota. It also explains the endemic corruption in tribal or clan-oriented societies like Afghanistan.

Conversely, radical universalist regimes—even bad ones like the Taliban—can cut down on corruption. https://www.americanprogress.org/article/tackling-corruption.... It’s possible that the low levels of corruption in New England, compared to the rest of the country, is the legacy of the radically universalist Puritans.