Greens sanctioned peace agreements, putting Republican out (8)
I believe the answer is:
lettuces
'peace agreements putting republican out' is the definition.
I can't judge whether this definition defines the answer.
'greens sanctioned' is the wordplay.
'greens' becomes 'lettuce' (lettuce is a kind of greens).
'sanctioned' becomes 's' (this might be a standard abbreviation I've not previously seen).
'lettuce'+'s'='LETTUCES'
Can you help me to learn more?
(Other definitions for lettuces that I've seen before include "Green leaves for salads" , "Green leaves for salad" , "Cos and Iceberg, say" .)