The first thing to admit when reviewing this film is that I don't know much about – or have a particular liking for – Westerns. I had a preconceived notion of what I thought John Ford movies were like, but after watching The Man Who Shot Liberty Valance I think I may have been getting him mixed up with Sergio Leone and Sam Peckinpah. I was really surprised by how much comedy there was, from the bumbling and cowardly Marshall to the alcoholic newspaper owner.

That's in stark contrast to anything concerning the titular villain, Lee Marvin playing Valance as a violent, bloodthirsty bully. Young, idealistic lawyer Ransom Stoddard (James Stewart) comes up against Liberty and his gang when the latter holds up the stagecoach Ransom's riding into the town of Shinbone seeking his fortune as a small town lawyer. When he stands up for himself Liberty beats him mercilessly and leaves him for dead in the desert.

We cut to Shinbone where local rancher Tom Doniphon (John Wayne) and his friend Pompey (Woody Strode) – he's a ranch hand, though there's a strong slavery allusion – ride into town with Ransom's unconscious, injured body. They deliver him to the family who owns the local restaurant and whose daughter, Hallie (Vera Miles) Tom is half-secretly sweet on, and they gradually nurse him back to health, giving him a temporary living and shelter in the restaurant kitchen.

As he gets to know the townsfolk, Ransom comes to understand the reign of terror Liberty's gang has always held over the area, but that the buffoonish Marshall (Andy Devine) – too chicken to do anything about Valance – gives him free reign by claiming anything outside town isn't his jurisdiction.

Ransom is appalled at the lack of law and order and won't hear of Tom's continued assertions that the only justice in the frontier comes at the barrel of a gun. He's determined to see Valance get what's coming to him by legal means and sets up his practice with the support of the newspaper publisher, Dutton Peabody (Edmond O'Brien) to go about it.

The truth about the event the title refers to is the lynchpin around which the story turns. It's all bookended by a much older Ransom – now a Senator and married to Hallie – returning to Shinbone for Tom's funeral. The rest of the tale is a flashback as he sits down to tell those gathered the truth about who shot Liberty Valance, even though the whole town thinks they saw Ransom himself do so.

In amongst it all is a subplot about the effort for Shinbone's territory to be granted statehood and wrest control away from the ranchers that ran the land with impunity without government mandated order, making it a political and historical tale.

Near the end, the action moves to Capital City for the statehood conference for such a long time (and with such obvious political leanings) it makes you wonder if Ford was making an impassioned plea for socialism, just like Charlie Chaplin did when he broke the fourth wall near the end of The Great Dictator to rail against fascism.

It renders the story of Liberty and Ransom's impending showdown – no matter how central – almost a footnote to introduce the larger theme. The story's actually about the unstoppable onset of modernity and the need to help usher it in to protect the masses from the forces of oppression.

Ransom is the hero for believing in a land where the law protects everyone and we don't all need to walk around with guns. Tom represents the old way that's dying out – possibly made emblematic by the fact that his death is the instigating event of the story – that The West is a dog eat dog land of those who know how to shoot and those who's days are numbered if they don't.

They're of course both right. It's only through extreme luck (and Tom's style of justice, which we don't learn until much later and which I won't spoil here) that Valance doesn't kill Ransom like he keeps threatening. But Ransom's belief in the sanctity of law and order is what allows for the flight to Capital City to cement the institution that will ultimately free Shinbone from having to live under such a regime at all.

Ford apparently hated any kind of film analysis, so maybe he didn't notice this – or maybe it was something intended more by writers James Warner Bellah and Willis Goldbeck, adapting Dorothy M Johnson's novel – but it seemed to be a comment on the end of the era it depicted as well as the Golden Age of Westerns themselves, which had begun under Ford 20 years earlier.

It's also the best depiction of John Wayne you've always imagined with his drawl and liberal use of the word 'pilgrim', and it's a great place to start if you don't know much about the Ford-era Western movement.