Soporific plant left world leader losing power (5)
I believe the answer is:
lotus
'soporific' is the definition.
(thesaurus)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for lotus that I've seen before include "British sports and racing car manufacturer" , "Sacred symbol" , "Plant widely regarded as sacred" , "Water-lily; yoga position" , "Mythical fruit including stste of dreaminess" .)