American city beginning to turn Liberal in America (5)
I believe the answer is:
tulsa
'american city' is the definition.
(I've seen this before)
'beginning to turn liberal in america' is the wordplay.
'beginning to' suggests taking the first letters.
'liberal' becomes 'l' (abbreviation).
'in' is an insertion indicator.
'america' becomes 'usa' (United States of America).
The first letter of 'turn' is 't'.
'l' placed within 'usa' is 'ulsa'.
't'+'ulsa'='TULSA'
(Other definitions for tulsa that I've seen before include "Oklahoma river port" , "OK city" , "Oklahoman city" , "Oklahoma city (only 24 hours away?)" , "Major oil centre" .)