Resolve to give irregular dimeter to the country (13)
I believe the answer is:
determination
'resolve' is the definition.
(I know that determination is a type of resolve)
'give irregular dimeter to the country' is the wordplay.
'give' says to put letters next to each other.
'irregular' is an anagram indicator.
'to the country' becomes 'nation' ('nation' can be a synonym of 'country').
'dimeter' is an anagram of 'determi'.
'determi' put next to 'nation' is 'DETERMINATION'.
'to' is the link.
(Other definitions for determination that I've seen before include "Perseverance" , "Firmness of purpose" , "Firm resolve" , "24 [DRIVE]" , "legal decision" .)