Delay American writer in South Dakota (7)
I believe the answer is:
suspend
'delay' is the definition.
(I know that suspend is a more specific form of the action defer)
'american writer in south dakota' is the wordplay.
'american' becomes 'US' (United States).
'writer' becomes 'pen' (something which writes).
'in' means one lot of letters goes inside another.
'south dakota' becomes 'sd' (abbreviation).
'us'+'pen'='uspen'
'uspen' placed into 'sd' is 'SUSPEND'.
(Other definitions for suspend that I've seen before include "Temporarily debar" , "Carry out hanging" , "Dangle or postpone" , "Fail to hit" , "Ban" .)