Obstinate type describes elected American congressman originally as very unimportant (9)
I believe the answer is:
minuscule
'very unimportant' is the definition.
'minuscule' can be an answer for 'unimportant' (I've seen this before). I'm not sure about the 'very' bit.
'obstinate type describes elected american congressman originally' is the wordplay.
'obstinate type' becomes 'mule' (I am not sure about this - if you are sure you should believe this answer much more).
'describes' is an insertion indicator (describe can mean to form the outline of).
'elected' becomes 'in'.
'american' becomes 'us'.
'originally' suggests taking the first letters.
The initial letter of 'congressman' is 'c'.
'in'+'us'+'c'='inusc'
'mule' placed around 'inusc' is 'MINUSCULE'.
'as' acts as a link.
Can you help me to learn more?
(Other definitions for minuscule that I've seen before include "A lower-case letter" , "not capital" , "Extremely small, tiny" , "Fine" , "Not important" .)