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.

For months, Tesla shareholders were tormented by Elon Musk’s role in the administration of President Donald Trump. But any relief brought by his formal government exit last week quickly turned to fear as the electric-vehicle maker’s chief executive traded barbs with his former boss.