How should a corporate board respond to a CEO publicly insulting and shaming a sitting president? It’s not a question that most need to consider, since few chief executives dare to directly criticize the White House.

Comedian Jon Stewart said President Trump and billionaire Elon Musk are in a “pretend fight” in a podcast dropped hours before the two former allies took extraordinary public shots at each other. Trump and Musk were benefiting from each other in a big way before their fiery and public falling out that came to a…