Part of USA that's excited but slow to support Democrat (4,4)
I believe the answer is:
dust bowl
'part of usa' is the definition.
(region of the American midwest)
'excited but slow to support democrat' is the wordplay.
'excited' is an anagram indicator.
'to support' is a charade indicator (letters next to each other) (in a down clue, some letters hold others up).
'democrat' becomes 'd'.
'but'+'slow'='butslow'
'butslow' anagrammed gives 'ustbowl'.
'ustbowl' after 'd' is 'DUST-BOWL'.
'that's' is the link.
(Other definitions for dust bowl that I've seen before include "Drought-stricken prairies in the US that suffered storms of fine powder in the 1930s" , "Result of drought, bad farming" , "Place that's dry" , "Drought area in the US" .)