Soviet aerial could be rusty? (7)
I believe the answer is:
reddish
'be rusty?' is the definition.
(thesaurus)
'soviet aerial' is the wordplay.
'soviet' becomes 'red' (red can informally mean communist).
'aerial' becomes 'dish aerial' (dish aerial is a kind of aerial).
'red'+'dish'='REDDISH'
'could' is the link.
(Other definitions for reddish that I've seen before include "terracotta lining?" , "Quite crimson" , "of mixed colour" , "Sort of ruby coloured" , "Rusty; slightly blushing" .)