Essential operation verifying sanction (6)

I believe the answer is:

ratify

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

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

(Other definitions for ratify that I've seen before include "Formally consent to (treaty)" , "Give formal approval to" , "Affirm" , "Fit ray (anag.)" , "Authorise" .)

I've seen this clue in The Irish Times.

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