We spot the breath coming from the authorities (3,6,4,2)

I believe the answer is:

the powers that be

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'authorities' is the definition.
(I've seen this before)

I don't understand how the rest of the clue works.

(Other definitions for the powers that be that I've seen before include "those with influence?" , "Existing exponents" , "Authorities" , "those in authority?" , "those who rule?" .)

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

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