Possible Clues:

• Not quite right
• Off-center
• Preoccupied with arcane details
• Not straight
• Faulty, unsound
• Not quite straight as a policy adviser?
• Crooked, askew
• Out-of-tune backing in 'God Only Knows'
• A bit unstable, like one obsessed with political details?
• Knowledgeable on arcane details of a subject