We know that the pendulum of political affiliation swings on a regular basis in most democracies.
I therefore conclude that with the presence of Trump on one side of the political alignment and Senator Sanders on the other, that we are at a major inflection point in the pendulum swing.
These two are men of extreme politics. Trump has a history of personal political chaos with no particular partisan leaning. He has picked out a political posture that pushes the extremist policy stand in a range of issues. As of the end of August 2015 his positions are still within the Republican domain. But he choses the extremist elements of those policies.
Senator Sanders is by far the most extreme Democrat to run for president in American history. An open 19th Century socialist. He is explicit about his position.
I believe that when the two parties have swung into such extreme domains, that coincides with the inflexion point in the society. The public is ready for a major directional change.
In the past the Republicans have had extremists like Pat Buchanan and the Democrats have had Barbara Jordan.
The country has been shifting in the moderate range from 1990 until 2008. Then came the election of a 2/3rds Democrat congress and an distinctly different and unqualified president. The pendulum has now moved against the Democrats to a very strong pro commerce, anti-union, anti-statist position.
I make predictions so I can learn.