In general today, most democracies in in the Americas use a presidential system, while most European countries use a parliamentary system. There are some notable exceptions, but that is the general trend. What could be changed in history that would reverse this, causing most American countries to use parliamentary systems and most European countries to use presidential system? Pre 1900 PODs are fine.
I have a vague idea for the Americas, but I haven't really though out specifics. In the Americas, I think that if the United States had used a parliamentary system from the start that would have spread to Latin America. I don't know how we could get the US to use a parliamentary system, though. I don't really know what could cause this in Europe, but that's why I'm asking for input.