Go in force for campaign (10)
I believe the answer is:
enterprise
'campaign' is the definition.
(thesaurus)
'go in force' is the wordplay.
'go in' becomes 'enter' ('enter' can be a synonym of 'go in').
'force' becomes 'prise' (I've seen this before).
'enter'+'prise'='ENTERPRISE'
'for' is the link.
(Other definitions for enterprise that I've seen before include "Bold resourcefulness" , "Project, undertaking" , "audacity" , "Initiative - undertaking - business" , "business concern" .)