Judges have troublesome supremacist cast out (7)
I believe the answer is:
umpires
'judges' is the definition.
(umpires make judgements on the rules)
'troublesome supremacist cast out' is the wordplay.
'troublesome' indicates anagramming the letters.
'out' is a deletion indicator.
'supremacist' with 'cast' taken out is 'upremis'.
'upremis' is an anagram of 'UMPIRES'.
'have' is the link.
(Other definitions for umpires that I've seen before include "Officials at cricket matches" , "Sports adjudicators" , "Referees for cricket marches" , "Officials at cricket match" , "they want fair play" .)