Ortega's extremists seizing some power back in capital (6)
I believe the answer is:
ottawa
'capital' is the definition.
(capital of Canada)
'ortega's extremists seizing some power back' is the wordplay.
'extremists' suggests removing the centre (letters on the extreme ends of the word).
'seizing' means one lot of letters goes inside another (inserted letters are seized).
'some power' becomes 'watt' (I've seen this before).
'back' shows that the letters should be reversed in order.
'ortega' with its middle taken out is 'oa'.
'watt' written backwards gives 'ttaw'.
'oa' enclosing 'ttaw' is 'OTTAWA'.
'in' is the link.
(Other definitions for ottawa that I've seen before include "N. American city" , "capital city" , "Canadian capital" , "North American city" , "somewhere in Canada" .)