Mr. Musk is fundamentally a creature of Silicon Valley, a scene that initiated an entire revolution in power dressing. The young masters of that universe dressed down to show that they were members of a new elite — one that refused to dress like the grown-ups they were about to topple. It was the defeat of the suit by the T-shirt.

A billionaire venture capitalist who has known Elon Musk for decades says there’s one crucial thing that Americans should understand about how the adviser to President Donald Trump operates. Musk doesn’t value the opinions of other people,