Send-off for dumped politicians? (5,4,5)

I believe the answer is:

going away party

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'dumped politicians?' is the definition.
I know nothing about this answer so I can't judge whether it can be defined by this definition.

'send-off' is the wordplay.
I cannot really understand how this works, but
'off' could be 'going' (I've seen this before) and 'going' is found in the answer.
This may be the basis of clue (or it may be nonsense).

'for' acts as a link.

Can you help me to learn more?

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

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