Paper supporting American in dispute (2,5)
I believe the answer is:
at issue
'in dispute' is the definition.
('at issue' can be a synonym of 'in dispute')
'paper supporting american' is the wordplay.
'paper' becomes 'tissue' (tissue is a kind of paper).
'supporting' says to put letters next to each other (in a down clue, some letters go below others).
'american' becomes 'a' (common abbreviation - e.g. in organisation names).
'tissue' put after 'a' is 'AT ISSUE'.
(Other definitions for at issue that I've seen before include "Questionable" , "under debate" , "in dispute" , "In question, under discussion" , "Being discussed or disputed" .)