Leaders of an unusual political alliance, in reality, a proponent of the nanny state perhaps (2,4)
I believe the answer is:
au pair
'a proponent of the nanny state perhaps' is the definition.
I can't tell whether this defines the answer.
'leaders of an unusual political alliance in reality' is the wordplay.
'leaders of' suggests taking the first letters.
The initial letters of 'an unusual political alliance in reality' is 'AU PAIR'.
Can you help me to learn more?
(Other definitions for au pair that I've seen before include "Live-in young foreigner expected to do household chores" , "Young foreign student" , "Young foreign person offering domestic help in exchange for lodgings" , "Live-in carer from abroad" , "Young, foreign baby-sitter" .)