A firm grasp of what hunger strikers aim to do (4,4)

I believe the answer is:

hold fast

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'a firm grasp' is the definition.
'hold fast' can be an answer for 'grasp' (thesaurus). I'm unsure of the 'a firm' bit.

I cannot understand how the rest of the clue works.

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I've seen this clue in The Globe and Mail.

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