The normal restrictions for political groups (7)
I believe the answer is:
'political groups' is the definition.
(I've seen this in another clue)
'the normal restrictions' is the wordplay.
'the normal' becomes 'par' (I've seen this in another clue).
'restrictions' becomes 'ties'.
'for' acts as a link.
(Other definitions for parties that I've seen before include "celebratory occasions" , "They may be thrown" , "Social gatherings" , "Celebrates" , "Celebrations" .)