Commander elected once more (5)
I believe the answer is:
again
'once more' is the definition.
(synonyms)
'commander elected' is the wordplay.
'commander' becomes 'aga' (I've seen this before).
'elected' becomes 'in' (in government).
'aga'+'in'='AGAIN'
(Other definitions for again that I've seen before include "Furthermore" , "second term" , "repeat order" , "On the other hand" , "Not for the first time" .)