Being disabled, elected Virginia Democrat is taking lithium (7)
I believe the answer is:
invalid
'being disabled' is the definition.
(thesaurus)
'elected virginia democrat is taking lithium' is the wordplay.
'elected' becomes 'in'.
'virginia' becomes 'va' (US state abbreviation).
'democrat' becomes 'd'.
'is taking' indicates putting letters inside.
'lithium' becomes 'li' (Li is the chemical symbol for lithium).
'va'+'d'='vad'
'vad' placed around 'li' is 'valid'.
'in'+'valid'='INVALID'
(Other definitions for invalid that I've seen before include "Having no effect" , "lacking legal authority" , "Legally void" , "Disable" , "Flawed" .)