Lincoln’s state banker failing: only a shilling in it (8)
I believe the answer is:
nebraska
'lincoln's state' is the definition.
(Lincoln is the state capital of Nebraska)
'banker failing only a shilling in it' is the wordplay.
'failing' indicates an anagram.
'only a shilling' becomes 'a s' (a single shilling, 1s).
'in it' is an insertion indicator.
'banker' anagrammed gives 'nebrka'.
'nebrka' going around 'as' is 'NEBRASKA'.
(Other definitions for nebraska that I've seen before include "Mid-western US state" , "Find snake bar in this US state" , "State N. of Kansas" , "Where Lincoln found" , "American state, capital Lincoln" .)