Backing unsettled Poles to take America to heart (8)
I believe the answer is:
espousal
'backing' is the definition.
(espousal is supporting or backing an idea)
'unsettled poles to take america to heart' is the wordplay.
I cannot quite see how this works, but
'america' could be 'usa' (synonyms) and 'usa' is located in the answer.
an anagram of 'poles' is 'espol' which is within the left over letters.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for espousal that I've seen before include "championship" , "Action of adopting (a cause)" , "Adoption (of a cause) - USA's pole (anag)" , "Adoption, support (of)" , "Acceptance with approval" .)