Judgement posted before Vice President loses power (8)
I believe the answer is:
sentence
'judgement' is the definition.
(sentence is a kind of judgement)
'posted before vice president loses power' is the wordplay.
I cannot really understand how this works, but
'posted' could be 'sent' ('send' can be a synonym of 'post') and 'sent' is found within the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for sentence that I've seen before include "Punishment awarded by court, or a set of words" , "Court judgement" , "life perhaps" , "Judicial penalty" , "Period of imprisonment" .)