State line request splitting temperance movement (6)
I believe the answer is:
alaska
'state' is the definition.
(Alaska is a US state)
'line request splitting temperance movement' is the wordplay.
'line' becomes 'l' (used when specifying particular lines from a poem).
'request' becomes 'ask' (to ask is to request something).
'splitting' is an insertion indicator (some letters split a word into two).
'temperance movement' becomes 'aa' (I can't justify this - if you can you should believe this answer much more).
'l'+'ask'='lask'
'lask' inserted into 'aa' is 'ALASKA'.
Can you help me to learn more?
(Other definitions for alaska that I've seen before include "Isolated US state" , "Most northerly US state" , "Most northerly state of America" , "American state, capital Juneau" , "Largest state of the USA" .)