Devastate second member of Tea Party (7)
I believe the answer is:
shatter
'devastate' is the definition.
(thesaurus)
'second member of tea party' is the wordplay.
'second' becomes 's' (common abbreviation).
'member of tea party' becomes 'hatter' (reference to the Mad Hatter in Alice in Wonderland).
's'+'hatter'='SHATTER'
(Other definitions for shatter that I've seen before include "Ruin" , "Support for broken arm" , "Threats (anag.)" , "Break the minister into little pieces" , "Crack" .)