Mars case for enrolment on left-wing scheme (3,6)
I believe the answer is:
red planet
'mars' is the definition.
('Red Planet' can be a synonym of 'mars')
'case for enrolment on left-wing scheme' is the wordplay.
'case for' says to hollow out the word (remove centre letters) (the letters which encase the others are used).
'on' is a charade indicator (letters next to each other).
'left wing' becomes 'red' (I've seen this in other clues).
'scheme' becomes 'plan' (I've seen this before).
'enrolment' with its centre taken out is 'et'.
'red'+'plan'='redplan'
'et' after 'redplan' is 'RED PLANET'.
(Other definitions for red planet that I've seen before include "celestial body" , "Informal name for Mars" , "object in 21 [SPACE]" , "Mars is colourfully known as the . . . . . . . . ." , "Colourful description of Mars" .)