Male Liberal passes on cards — everyone must get involved (3,5,2,4)
I believe the answer is:
all hands on deck
'everyone must get involved' is the definition.
'male liberal passes on cards' is the wordplay.
'male' becomes 'al' (shortened version of Alex or Alistair).
'liberal' becomes 'l' (abbreviation).
'passes' becomes 'hands' ('hand' can be a synonym of 'pass'**).
'cards' becomes 'deck' (I've seen this before).
'al'+'l'+'hands'+'on'+'deck'='ALL HANDS ON DECK'
(Other definitions for all hands on deck that I've seen before include "Alert for everyone" , "Order, on board" .)