Times has often run leaders as “The Thunderer” (4)
I believe the answer is:
thor
'the thunderer' is the definition.
(Norse thunder god)
'times has often run leaders' is the wordplay.
'leaders' indicates taking the first letters.
The first letters of 'times has often run' is 'THOR'.
'as' acts as a link.
(Other definitions for thor that I've seen before include "Scandinavian thunder-god" , "Norse hammer-wielding god" , "Norse god of thunder - a weekday is named after him" , "Imitative artistic work" , "can be classed as immortal" .)