Equality enjoyed by one in political group (6)
I believe the answer is:
parity
'equality' is the definition.
(I know that parity is a type of equivalence)
'one in political group' is the wordplay.
'one' becomes 'I' (Roman numeral).
'in' is an insertion indicator.
'political group' becomes 'party' (a political party).
'i' inserted inside 'party' is 'PARITY'.
'enjoyed by' is the link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for parity that I've seen before include "Correspondence" , "equal treatment" , "state of equality" , "Equality, equivalence" , "Egalitarian goal" .)