Horrible attritional aims in dictatorship? (15)
I believe the answer is:
totalitarianism
'dictatorship?' is the definition.
(synonyms)
'horrible attritional aims' is the wordplay.
'horrible' is an anagram indicator.
'attritional'+'aims'='attritionalaims'
'attritionalaims' is an anagram of 'TOTALITARIANISM'.
'in' acts as a link.
(Other definitions for totalitarianism that I've seen before include "Allowing no opposition" , "Dictatorship" .)