Campaign speech incorporating empty prose (9)
I believe the answer is:
operation
'campaign' is the definition.
(thesaurus)
'speech incorporating empty prose' is the wordplay.
'speech' becomes 'oration' (oration is a kind of speech).
'incorporating' means one lot of letters goes inside another.
'empty' means to remove the middle letters.
'prose' with its centre taken out is 'pe'.
'oration' enclosing 'pe' is 'OPERATION'.
(Other definitions for operation that I've seen before include "management" , "battle" , "In hospital procedure" , "Handling" , "Theatre procedure" .)