TV could show dope case (5,3)
I believe the answer is:
idiot box
'tv' is the definition.
(synonyms)
'dope case' is the wordplay.
'dope' becomes 'idiot' (I've seen this in another clue).
'case' becomes 'box' (boxing is a kind of casing).
'idiot'+'box'='IDIOT BOX'
'could show' is the link.
(Other definitions for idiot box that I've seen before include "TV (slang)" , "TV revealed" , "TV set (US colloq.)" , "tube" .)