The resignation of U.S. Defense Secretary James Mattis stands not only as a radical disassociation from the actions of the president he served, but as a foreboding for the future, a warning for 2019 – and beyond. And, for all the assurances that the world is getting better, such as Steven Pinker’s “Enlightenment Now,” there are huge geopolitical challenges to face and master to make that optimism real.

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