Possible Clues:

• Run off as one moves: silliness
• The absence of rationality or logic
• Casting rune, a relative produces nonsense
• Angry trade unions striking? It'd be nonsense
• Mostly mock child showing a lack of sense
• Peacekeepers find grounds for madness
• Endlessly jittery about accepting Republican irrationality
• Folly
• Run on sea? That's irrational
• Lack of logic: answer is found in decay of neurons