Line travelled by new ruler (5)
I believe the answer is:
lenin
'ruler' is the definition.
(Vladimir Lenin)
'line travelled by new' is the wordplay.
'travelled' is an anagram indicator.
'by' says to put letters next to each other.
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'line' anagrammed gives 'leni'.
'leni'+'n'='LENIN'
(Other definitions for lenin that I've seen before include "Russian revolutionary" , "Linen for Communist" , "Early Soviet leader" , "Vladimir Ilyich -, Soviet premier" , "Soviet Union's first premier" .)