Church split by concerning democratic dogma (5)
I believe the answer is:
creed
'dogma' is the definition.
(I've seen this in another clue)
'church split by concerning democratic' is the wordplay.
'church' becomes 'CE' (abbreviation for Church of England).
'split by' is an insertion indicator.
'concerning' becomes 're' (both can mean on a particular topic).
'democratic' becomes 'd' (political abbreviation).
'ce' going around 're' is 'cree'.
'cree'+'d'='CREED'
(Other definitions for creed that I've seen before include "Religious doctrine" , "Statement of belief" , "System of religious belief" , "restricted set of principles" , "System of belief, faith" .)