It’s hard to put a leash on a dog once you’ve put a crown on its head.

The line uses a blunt animal metaphor to describe the political difficulty of reversing empowerment. Once someone (or some faction) has been elevated—given authority, legitimacy, or the symbols of rule (“a crown”)—they tend to act with the independence and entitlement of a ruler, not a subordinate. Trying to reassert control afterward (“put a leash on”) invites resistance, humiliation, or violence, because the new status changes expectations on both sides. In Martin’s world, this logic often applies to kings, warlords, and ambitious allies: making a tool of power can create a rival you can no longer safely restrain.