Rouse leading American party for the passing of final legislation (6)
I believe the answer is:
awaken
'party for the passing of final legislation' is the definition.
I can't judge whether this defines the answer.
'rouse leading american' is the wordplay.
'rouse' becomes 'waken' (I've seen this before).
'leading' says to put letters next to each other.
'american' becomes 'a' (common abbreviation - e.g. in organisation names).
'waken' after 'a' is 'AWAKEN'.
Can you help me to learn more?
(Other definitions for awaken that I've seen before include "Call forth" , "Emerge from sleep" , "Rouse (a feeling)" , "Come alive" , "Arouse" .)