President about to make a mistake with one state - it's not normal (9)
I believe the answer is:
aberrance
'one state it's not normal' is the definition.
I can't judge whether this definition defines the answer.
'president about to make a mistake with' is the wordplay.
'president' becomes 'abe' (Abraham (Abe) Lincoln).
'about' indicates putting letters inside.
'to make a mistake' becomes 'err' ('err' can be a synonym of 'make a mistake').
'with' becomes 'anc' (I can't justify this - if you can you should give a lot more credence to this answer).
'err'+'anc'='erranc'
'abe' placed around 'erranc' is 'ABERRANCE'.
Can you help me to learn more?
(Other definitions for aberrance that I've seen before include "Atypical behaviour" , "Deviation from normal" , "going in the wrong direction" .)