POTUS in trouble over wall, finally — that's natural (8)
I believe the answer is:
unspoilt
'natural' is the definition.
(I've seen this before)
'potus in trouble over wall finally' is the wordplay.
'trouble' indicates anagramming the letters.
'over' indicates putting letters inside.
'finally' suggests the final letters.
The last letter of 'wall' is 'l'.
'potus'+'in'='potusin'
'potusin' anagrammed gives 'unspoit'.
'unspoit' enclosing 'l' is 'UNSPOILT'.
'that's' is the link.
(Other definitions for unspoilt that I've seen before include "Natural, not ruined" , "Not harmed/damaged" , "Preserved" , "Not impaired or ruined" , "Not ruined by development" .)