Possible Clues:

• The law of retaliation (2,3,3,2,3)
• A fair exchange in sight? (2,3,3,2,3)
• Retribution with an exchange of views? (2,3,3,2,3)
• A fair exchange in sight
• See to it that you get another in exchange (2,3,3,2,3)
• Tit for tat (2, 3, 3, 2, 3)
• This sounds nigh - foreign nigh for vengeance (2, 3, 3, 2, 3)
• Retaliation principle (2,3,3,2,3)
• I4I, perhaps, to make it all square (2,3,3,2,3)