I know the urge of many people (Me included) to call modern Brazil as that, but I don't want this to result on a chat like discussion and my objective is to keep the debate with a 20th century PoD to fit this forum, so here it goes:
The challenge is to make Brazil something dystopic, but not "fallout" like dystopic after a nuclear war or a foreign invasion. The idea is that the country structure breaks apart on a situation similar — if not worse — to the old republic (1889-1930). Basically corruption to make 90s Russia looks like Germany, local militias controlling everything and even the most basic government positions being corrupted to the core.