Bias of papers covering party (10)
I believe the answer is:
prepossess
'bias' is the definition.
(I know that bias is a more specific form of the action prepossess)
'papers covering party' is the wordplay.
'papers' becomes 'press' (the newspaper industry).
'covering' is an insertion indicator.
'party' becomes 'posse' (I can't justify this - if you can you should believe this answer much more).
'press' enclosing 'posse' is 'PREPOSSESS'.
'of' acts as a link.
Can you help me to learn more?
(Other definitions for prepossess that I've seen before include "Bias favourably" , "Influence" .)