Rich politician turned out in America, swinging both ways (9)
I believe the answer is:
sumptuous
'rich' is the definition.
(similar in meaning)
I can't explain the remainder of the clue.
(Other definitions for sumptuous that I've seen before include "Grand" , "Luxurious" , "Magnificent" , "Delicious and expensive" , "Splendid, rich" .)