Journalist supporting political party, taken for a ride (5)
I believe the answer is:
duped
'taken for a ride' is the definition.
(I've seen this in another clue)
'journalist supporting political party' is the wordplay.
'journalist' becomes 'ed' (short for editor).
'supporting' says to put letters next to each other (in a down clue, some letters go below others).
'political party' becomes 'dup' (Democratic Unionist Party).
'ed' put after 'dup' is 'DUPED'.
(Other definitions for duped that I've seen before include "Hoaxed" , "Bamboozled" , "Hoodwinked and misled" , "Tricked" , "Taken for a ride" .)