Appeared united after end of debate (7)
I believe the answer is:
emerged
'appeared' is the definition.
(emerging is a kind of appearing)
'united after end of debate' is the wordplay.
'united' becomes 'merged' ('merge' can be a synonym of 'unite'**).
'after' says to put letters next to each other.
'end of' suggests the final letters.
The last letter of 'debate' is 'e'.
'merged' after 'e' is 'EMERGED'.
(Other definitions for emerged that I've seen before include "Emanated" , "Slowly came out" , "Came out, became known" , "Transpired" , "Deem Reg to have come out" .)