Encourage liberal nonsense (6)
I believe the answer is:
drivel
'nonsense' is the definition.
(drivel can mean nonsensical speech or writing)
'encourage liberal' is the wordplay.
'encourage' becomes 'drive' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'liberal' becomes 'l' (abbreviation).
'drive'+'l'='DRIVEL'
Can you help me to learn more?
(Other definitions for drivel that I've seen before include "Verbal nonsense, rubbish" , "Balls" , "Worthless talk" , "Silly talk, twaddle" , "Silly talk, sheer nonsense" .)