In favour of church using coercion... (5)
I believe the answer is:
force
'coercion' is the definition.
(thesaurus)
'in favour of church' is the wordplay.
'in favour of' becomes 'for' (I've seen this before).
'church' becomes 'ce' (abbreviation for Church of England).
'for'+'ce'='FORCE'
'using' acts as a link.
(Other definitions for force that I've seen before include "Urge" , "Compulsion - police" , "'Compel, pressurise (5)'" , "Powerful effect or influence" , "Compel, oblige" .)