New line by new Bolshevik (5)
I believe the answer is:
lenin
'bolshevik' is the definition.
(I know that Lenin is a bolshevik)
'new line by new' is the wordplay.
'new' indicates anagramming the letters.
'by' is a charade indicator (letters next to each other).
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'line' is an anagram of 'leni'.
'leni'+'n'='LENIN'
(Other definitions for lenin that I've seen before include "Marxist theoretician" , "First premier of the Soviet Union, d. 1924" , "Vladimir Ilich Ulyanov" , "Soviet Union's first premier" , "Vladimir Ilyich -, Soviet premier" .)