A very different matter from American revolutionary party lines (1,3,3)
I believe the answer is:
a far cry
'revolutionary party lines' is the definition.
I know nothing about this answer so I can't judge whether this works.
'a very different matter from american' is the wordplay.
I cannot quite understand how this works, but
'a' is found in the answer.
'matter' could be 'cr' (Cr is an example) and 'cr' is located in the answer.
'american' could be 'a' (common abbreviation - e.g. in organisation names) and 'a' is found within the answer.
'from' could be 'fr' (abbreviation) and 'fr' is found within the remaining letters.
A single letter 'y' remains which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for a far cry that I've seen before include "another cup of tea" , "something very different" , "Greatly different, like a distant shout" , "Yodel" , "That's a very different matter" .)