Gives a party a new constitution perhaps (8)

'gives' is the definition.
The answer and definition can be both related to thinking as well as being verbs in their -s form.
Perhaps there's an association between them I don't understand?

'a party a new constitution perhaps' is the wordplay.
I cannot quite see how this works, but
'party' could be 'group' (group of people) and 'group' is found within the answer.
The remaining letters 'res' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).

Can you help me to learn more?