Extremely reprehensible landlord, one who voted for Trump? (10)
I believe the answer is:
republican
'one who voted for trump?' is the definition.
(Donald Trump was a Republican US president)
'extremely reprehensible landlord' is the wordplay.
'extremely' suggests removing the centre (only the extremes of the word are used).
'landlord' becomes 'publican' (as in a pub landlord).
'reprehensible' with its centre removed is 're'.
're'+'publican'='REPUBLICAN'
(Other definitions for republican that I've seen before include "American in party" , "Eg Lincoln" , "in foreign party" , "Member of US political party" , "anti-monarchist" .)