Sentence:  During the next five years liberal leaders in the United States sank in the cumulative confusion attendant upon and <WSD>manifested</WSD> in a negative policy of Containment - and the bitterest irony - enforced and enforceable only by threat of a weapon that we felt the greatest distaste for but could not abandon : 
Meaning of the word marked with <WSD> tags:  provide evidence for; stand as proof of; show by one's behavior, attitude, or external attributes