Justice failed Poles, hints a Soviet invader (6,6)

I believe the answer is:

joseph stalin

I'm a little stuck... Click here to teach me more about this clue!

'soviet invader' is the definition.
The definition and answer can be both people as well as being singular nouns.
Perhaps you can see a link between them that I don't see?

'justice failed poles hints a' is the wordplay.
'justice' becomes 'j'.
'failed' indicates an anagram.
'poles'+'hints'+'a'='poleshintsa'
'poleshintsa' is an anagram of 'osephstalin'.
'j'+'osephstalin'='JOSEPH STALIN'

Can you help me to learn more?

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

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