North America succeeded, primarily swapping gold for capital in the Caribbean (6)
I believe the answer is:
nassau
'capital in the caribbean' is the definition.
(capital of The Bahamas)
'north america succeeded primarily swapping gold' is the wordplay.
'north america' becomes 'na'.
'succeeded' becomes 's' (genealogical abbreviation).
'primarily' suggests taking the first letters.
'gold' becomes 'Au' (Au is the chemical symbol for gold).
The first letter of 'swapping' is 's'.
'na'+'s'+'s'+'au'='NASSAU'
'for' is the link.
(Other definitions for nassau that I've seen before include "Caribbean resort" , "Saunas (anag)" , "Bahamas cap." , "city" , "Dublin street in the Bahamas?" .)