Political theory backing strike — is money after a vote? (7)
I believe the answer is:
marxism
'political theory' is the definition.
(I've seen this before)
'backing strike is money after a vote?' is the wordplay.
'backing strike' becomes 'mar' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'money' becomes 'm' (abbreviation in economics).
'after' means one lot of letters go next to another.
'a vote?' becomes 'x' (how votes are marked).
'is'+'m'='ism'
'ism' after 'x' is 'xism'.
'mar'+'xism'='MARXISM'
(Other definitions for marxism that I've seen before include "Political doctrine" , "political philosophy?" , "Left-wing ideology" , "Left-wing philosophy" , "Basis of communism" .)