During the last few weeks of Donald Trump’s presidential campaign in the fall of 2016, I found myself seeking out increasingly tender and empathetic photographs of his supporters. Maybe it was the long weeks away from my own son that softened my eye and drew me toward parents and their children at Mr. Trump’s rallies. It’d been a long journey covering the campaign, and I remember being exhausted by the anger I experienced. The crowds took Mr. Trump’s lead and directed their hatred at me and my colleagues from the press, event after event, day after day, and, eventually, it...