Related Clues:

• See 59 Down
• NBAer, e.g.
• Quid ___ quo
• Slugger Mel, for one
• Supporter's side
• Active leader?
• Debate position and half of this puzzle's theme
• Argument side
• Country-club instructor
• Professional, for short
• Any PGA member
• One who knows the ropes
• Debater's position, sometimes
• ___ bono
• Touring player