This post is on the connection between oversized majorities and waves of political reform. Here I am thinking about ranked-choice voting in historical context, though one might say the same about direct primaries. I think reforms like this take off when:
1) Most people lean to one side of the ideological spectrum;
2) But that side of the spectrum has serious, internal cleavages.
The basic idea is that the logic of minimum-winning coalition is not holding in some way. The political majority is oversized, so much of the action is inside it. That fighting finds expression first as party splits, then as reforms to foster coordination. I have floated this hypothesis before. Others are starting to touch on it. Let’s look at some data.