Students have trouble in Marxist concept (5,8)

I believe the answer is:

class struggle

'marxist concept' is the definition.

'students have trouble' is the wordplay.
'students' becomes 'class'.
'have trouble' becomes 'struggle'.
'class'+'struggle'='CLASS STRUGGLE'

'in' acts as a link.

(Another definition for class struggle that I've seen is " Conflict between workers and the ruling class".)

I've seen this clue in The Times.

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