The phrase 'Wag the Dog' is used to indicate that attention is purposely being diverted from something of greater importance to something of lesser importance.
Example of Use: “He’s wagging the dog to keep you from discovering the truth about the car wreck.”
The term 'wag the dog' comes from the expression that a dog is smarter than its tail, but if the tail were smarter than the dog, the tail would be in control.