Gather moderate Democrat will oust Republican (6)

I believe the answer is:

deduce

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'gather' is the definition.
(I've seen this in another clue)

I don't understand the rest of the clue.

(Other definitions for deduce that I've seen before include "Arrive at conclusion from studying facts" , "Reason through logic" , "Arrive at conclusion through logic" , "Reason out (something)" , "Conclude by reasoning" .)

I've seen this clue in The Independent.

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