Adoption by Poles wandering around the States (8)
I believe the answer is:
espousal
'adoption' is the definition.
(I've seen this before)
'poles wandering around the states' is the wordplay.
'wandering' indicates an anagram.
'around' indicates putting letters inside.
'the states' becomes 'usa' (United States of America).
'poles' anagrammed gives 'espol'.
'espol' enclosing 'usa' is 'ESPOUSAL'.
'by' acts as a link.
(Other definitions for espousal that I've seen before include "Adoption, support (of)" , "Favourable reception" , "Action of adopting (a cause)" , "Adoption (of a cause) - USA's pole (anag)" , "old-fashioned marriage" .)