Transport ecstasy left for political alliance (6)
I believe the answer is:
cartel
'political alliance' is the definition.
'cartel' can be an answer for 'alliance' (I've seen this in another clue). I am not sure about the 'political' bit.
'transport ecstasy left' is the wordplay.
'transport' becomes 'cart' (cart is a kind of transport).
'ecstasy' becomes 'E' (informal term for the drug).
'left' becomes 'l' (common abbreviation).
'cart'+'e'+'l'='CARTEL'
'for' is the link.
Can you help me to learn more?
(Other definitions for cartel that I've seen before include "Group formed to limit competition" , "Business syndicate in claret" , "Self-interest group who control prices" , "Manufacturer's association restricting competition" , "Manufacturers' group controlling market" .)