Perhaps China's promise to take liberal prisoner with Queen (5,5)

'perhaps china's' is the definition.
(China is a world power)

'liberal prisoner with queen' is the wordplay.
'liberal' becomes 'world' (I can't explain this - if you can you should give a lot more credence to this answer).
'prisoner' becomes 'POW' (POW is an example).
'with' says to put letters next to each other.
'queen' becomes 'ER' (abbreviation for Elizabeth Regina).
'world'+'pow'+'er'='WORLD POWER'

'promise to take' is the link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.