Democrat deprived of victory with Republican going out of action (8)
I believe the answer is:
demobbed
'going out of action' is the definition.
The answer and definition are different parts of speech. However, adjectives and past participle verbs can occasionally mean the same thing.
'democrat deprived of victory with republican' is the wordplay.
I cannot quite see how this works, but
'democrat' could be 'dem' (common abbreviation in US politics) and 'dem' is found within the answer.
'of' could be 'o' and 'o' is found in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for demobbed that I've seen before include "Retired from military service" , "Returned to civvy street" , "discharged" .)