The Trump juggernaut illustrates the challenge of prophecy. It illustrates the problem with a simple foreknowledge approach to providence. It illustrates the logic of open theism, if you grant the premise of libertarian freewill.
Trump's success has confounded the pundits. There are two reasons for that:
i) We are better at predicting the behavior of people who are like us. The case of Trumpkins generates a paradox. Many Trumpkins are low info voters. They don't know and they don't care. By contrast, pundits like Nate Silver, Michael Barone, Larry Sabato, Ross Douthat, Bill Kristol, Karl Rove, Ben Shapiro et al. are high info voters. They know a lot about the issues; they know a lot about the candidates.
The trick is how can a high info voter project himself into the mindset of a low info voter to anticipate what a low info voter will think and do. A high info voter views Trump in a completely different context than a low info voter. Ironically, that's a disadvantage in predicting the behavior of voters who lack that frame of reference. You must bracket what you know about Trump, bracket what you know about the issues, to assume the outlook of a Trumpkin.
ii) In addition, what's possible or probable depends on the state of play at any given time. Take two chess masters or poker champs. When they sit down at the table, they don't know ahead of time how they will play the game. There's a move/countermove dialectic that depends on what the prior move happens to be. Every move opens up a new set of forking paths. Different ways to win or lose. It's almost like every move is the first move. For every move resets the variables.