The theme of a great gunslinger/sheriff/marshall who has lost his nerve, is not a really rare theme in a W. movie. The Intruders [with Forbidden Planet Annie Francis] was such a movie (1970's, made for TV).
As I recall:
Around about the same time (1970's) that I saw The Intruders on TV years ago, another such movie was broadcast. The sheriff or marshall had come near dying from a gun fight; and after the near death from gun shot, he had lost his gun nerve. He was going around town not wearing a gun, living on his reputation.
In the climax, a gunslinger came to town & began acting as a bully. He displayed dazzling speed on the draw and deadly accuracy with his fire. Eventually the gunslinger confronted the sheriff & forced a gun fight with him. But when the gunslinger reached for his gun, he didn't even get it all the way out of the holster before the sheriff shot him (probably in the heart). As the gun slinger died he had an amazed look on his face and commented on how he didn't even get his gun out before the sheriff/marshal outdrew him & shot him (last words of the gunslinger).
Does anyone recall that movie and its title?