Campaigns making us scared (8)
I believe the answer is:
crusades
'campaigns' is the definition.
(crusading is a kind of campaigning)
'making us scared' is the wordplay.
'making' indicates an anagram.
'us'+'scared'='usscared'
'usscared' with letters rearranged gives 'CRUSADES'.
(Other definitions for crusades that I've seen before include "wars" , "Military expeditions by Christians to recapture the Holy Land" .)