Anticipation of wisdom keeping American quiet (8)
I believe the answer is:
suspense
'anticipation' is the definition.
(I know that suspense is a type of anticipation)
'wisdom keeping american quiet' is the wordplay.
'wisdom' becomes 'sense' (sense is a kind of wisdom).
'keeping' indicates putting letters inside.
'american' becomes 'us' (abbreviation for United States).
'quiet' becomes 'p' (music symbol for 'piano', ie soft or quiet).
'us'+'p'='usp'
'sense' enclosing 'usp' is 'SUSPENSE'.
'of' is the link.
(Other definitions for suspense that I've seen before include "Feeling of excitement or anxiety about what might happen" , "State of uncertainty or excitement" , "Excited anticipation of approaching climax" , "Discontinuance - indecision - excitement" , "State of anxiety or excitement" .)