Idiots accepting Democrat's backing for capital (6)
I believe the answer is:
assets
'for capital' is the definition.
(financial assets)
'idiots accepting democrat's backing' is the wordplay.
'idiots' becomes 'asses' (I've seen this before).
'accepting' is an insertion indicator.
'democrat's backing' becomes 't' (I can't justify this - if you can you should give a lot more credence to this answer).
'asses' enclosing 't' is 'ASSETS'.
Can you help me to learn more?
(Other definitions for assets that I've seen before include "Useful or valuable things" , "One's valuable possessions" , "Valuables, things worth having" , "Possessions and resources" , "(Person's) property" .)