A petty war organised by famous lawman (5,4)
I believe the answer is:
wyatt earp
'famous lawman' is the definition.
I know nothing about this answer so I can't tell whether this works.
'a petty war organised' is the wordplay.
'organised' indicates an anagram.
'a'+'petty'+'war'='apettywar'
'apettywar' with letters rearranged gives 'WYATT EARP'.
'by' is the link.
Can you help me to learn more?
(Other definitions for wyatt earp that I've seen before include "Victor at the 1 down" , "Participant in the gunfight at the OK Corral" .)