When your child dies, everything changes.

My daughter was not a soldier, fighting for her country oversees, risking her life to keep the rest of us safe and then surrendering it to save her troops. So I don’t know how it feels to be a Gold Star parent.

My daughter was just a 20-year-old Harvard junior crossing the street, a victim to poor driving, her own distraction, and the bloodthirsty traffic gods of Harvard Square. (It’s often occurred to me that she would have been safer in Israel, where terror attacks have led to great advances in the sort of emergency technology that can detangle dying brains from crashed metal, than she was in Cambridge, where time most definitely was not of the essence.) So I do know what it’s like to have that sudden monstrous stinking obscene hole in your life.

I know how that hole can be overgrown, how its edges can get fuzzy, how you can maybe even forget about it for a few hours at a time – and also I know how one misstep sends you blindsided into that foul abyss.

I don’t know what it feels like to be Khizr or Ghazala Khan. I’m not an immigrant and I’m not a Muslim; far more to the point, I’m not the mother of a soldier or sailor or airman or woman or Marine. But I do know what it feels like to be confronted with an obscene impossibility – that your beloved, so-very-alive child is dead, and that you are still alive, and that although you might like to you cannot die of grief.

Instead, you are sentenced to live with it.

So I understand the Khans, to some extent. I know that breach in goodness that is an inescapable part of their lives.

I do not understand Donald Trump. I do not understand how anyone can attack the parents of a dead child. No matter how illogical they sound, no matter how much off-putting their pain may be, no matter how petty they appear, no matter how tear-stained or overweight or unattractive, no matter how unimpressive their stories. None of that matters. All anyone should do when confronted with unimaginable pain (and if you haven’t felt it, you can’t imagine it) is shut up.

The Republican convention featured many parents of dead children. Their convictions were not always rational, and often their conclusions were unpalatable. They all were treated with respect by their listeners, by the Democratic party and its leadership, and by Hillary Clinton. No one questioned their motives, truthfulness, or basic decency.

That would have been indecent.

Donald Trump does not seem to be restrained by the bonds of ordinary decency, nor by any understanding of the limits of a normal imagination, and that, in turn, stretches our imaginations as we try to put ourselves in his mind. It is hard to imagine being so lacking in empathy as to believe that a child’s death is the equivalent of working hard and employing people. (Indeed, to most of us working hard and being in the position to employ people would not be a sacrifice but a positive goal, a very real good.)

To live through the death of a child is to live through and then with unspeakable pain. To live an entire life unable to understand any emotion other than your own, apparently unable to feel anything other than rage, jealousy, humiliation, dominance, and triumph, to be left ice stone cold by grief or by love, by sacrifice or nobility, though – that would be a pain beyond bearing.

Donald Trump attacks the Khans because he must. Sharks gotta swim, birds gotta fly, Trump’s gotta attack that man till…

He can’t help himself. It’s what he does. Those of us – that vast overwhelming majority of us – who feel empathy can watch with disgust, or even with fascination, but we must be clear about what we see. This is a man with no warmth, no empathy, no human compassion. That is a truth we cannot avoid.