When the tree is down, every one runs with his hatchet.

Once a person, institution, or cause has fallen into weakness or defeat, others may hasten to attack it, profit from it, or add to its damage because resistance seems unlikely.

The image warns that misfortune can attract opportunists rather than sympathy. It can also describe the piling-on that occurs after someone has lost authority, protection, or the ability to defend themselves.

Use it when a setback leaves someone or something exposed to criticism, exploitation, or further attack. It suits commentary on opportunistic behavior after a rival’s defeat or public loss of power, but apply it carefully when the subject is a real person’s hardship.