Brief work by bard on American states (5)
I believe the answer is:
avers
'states' is the definition.
(to aver is to declare or state)
'brief work by bard on american' is the wordplay.
I cannot quite understand how this works, but
'american' could be 'a' (common abbreviation - e.g. in organisation names) and 'a' is located in the answer.
The remaining letters 'vers' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for avers that I've seen before include "States positively" , "Alleges, asserts" , "Declares to be true" , "States firmly - really raves" , "States to be true" .)