What would be the cause/causes of "the next realignment"?
Judging by history and the 2016 election, I have hazarded at a guess the cause could be Federal public lands in the West. There has already been much debate about privatization of these lands, and how formidable might a third-party candidate radically in favour of such a move be in the West (except Washington state)??
The issue of Federal public lands in the West – which everywhere bar eastern Washington account for most land in the West – seems to me
a much bigger issue than anything in the 2016 election. There is from a scientific perspective no doubt that present management of the West’s land and water is badly flawed – huge water shortages in California and Arizona for a start, and complaints over access to grazing land in eastern Oregon for another suggest a radically different management system could certainly be plausibly better.