With no clear candidate emerging, success involves info about European (4-4)
I believe the answer is:
wide-open
'with no clear candidate emerging' is the definition.
(something wide open could be won by anyone)
'success involves info about european' is the wordplay.
'success' becomes 'win' (I've seen this in another clue).
'involves' indicates putting letters inside.
'info' becomes 'dope' (dope is a kind of info).
'about' means one lot of letters goes inside another.
'european' becomes 'E' (abbreviation e.g. EU).
'win' enclosing 'dope' is 'widopen'.
'widopen' enclosing 'e' is 'WIDE-OPEN'.
(Other definitions for wide-open that I've seen before include "Exposed to attack" , "Gaping -- very vulnerable" , "Vulnerable to attack (colloq.)" .)