They sought reds for host, caught suffering thirst, say (12)

I believe the answer is:

mccarthyists

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'they sought reds for host' is the definition.
The definition suggests an adverb but the answer is not.

'caught suffering thirst say' is the wordplay.
'caught' becomes 'mcc' (I can't explain this - if you can you should believe this answer much more).
'suffering' indicates anagramming the letters.
'thirst'+'say'='thirstsay'
'thirstsay' anagrammed gives 'arthyists'.
'mcc'+'arthyists'='MCCARTHYISTS'

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I've seen this clue in the Sydney Morning Herald.

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