Alternate Character Interpretation: Tom Doniphon was a coward. He shot Valance in secret and claimed credit in private, not to ease Stoddard's conscience over killing Valance, but to saddle him with a lifetime of guilt. Stoddard was the one who actually put his life on the line.
And while Ransom achieved great things for his adopted state - getting statehood, representing in Congress, working as Governor, bringing the roads, schools and gardens to the desert as Peabody envisioned - it still all happened based on a lie.
Hilarious in Hindsight: John Wayne as the straight shooting tough guy and James Stewart as the soft spoken pacifist becomes unintentionally funny when you consider that Stewart actually served in World War II and Wayne didn't. So Jimmy Stewart was actually far more of a tough guy than the Duke himself.
Ho Yay: Valance's sidekick Floyd seems to toady up to Liberty a little too much...
Also, "When the legend becomes fact, print the legend."
Misaimed Fandom: The quote about "print the legend" is often seen by moviegoers and critics as John Ford's defense of the "noble lie". However film historians note that this isn't Ford's intentions, since Ford in Liberty Valance showed the "making of the legend" and the consequences, lies and evasions that go into it and what it measn for Ransom to live that lie. As Peter Bogdanovich said, "Ford always printed the truth".
Moral Event Horizon: Liberty Valance enters the film with a nasty reputation and violent history, and gets worse as the movie progresses. It's his beating of Peabody to within an inch of the editor's life that riles up Ransom enough to get him to call the gunman out for a duel.
Vindicated by History: Contemporary critics treated Liberty Valance as, basically, just another John Wayne movie, though it did well at the box office. Over the years it's become recognized as one of Ford and Wayne's best films.