Republican Party without energy for overhaul (4)

I believe the answer is:
redo
'overhaul' is the definition.
The answer and definition can be both related to change as well as being verbs in their base form.
Perhaps they are linked in a way I don't understand?
'republican party without energy' is the wordplay.
'republican' becomes 'R' (abbreviation in US politics).
'party' becomes 'do' (do can informally mean a party).
'without' is an insertion indicator ('without' can be similar in meaning to 'outside').
'energy' becomes 'e' (physics symbol as in E=mc2).
'r'+'do'='rdo'
'rdo' enclosing 'e' is 'REDO'.
'for' is the link.
Can you help me to learn more?
(Other definitions for redo that I've seen before include "Have second thoughts" , "Start again" , "Make anew" , "Perform (action) again" , "Redecorate or repeat action" .)
