The Wonderful Country (1959)

In Robert Parrish's untraditional, intelligent and complex post-Civil War adult western - the Technicolored film was the 2nd of Robert Mitchum's DRM Productions, following Thunder Road (1958):

• the main character: white man "pistolero" - a brooding, introspective hired gun living in Mexico - American Martin Brady (Robert Mitchum), employed by Mexico's wealthy Governor Don Cipriano Castro (Pedro Armendáriz) who ruled the entire Northern Mexican state of Chihuahua, and was allied with Castro's ruthless younger brother Gen. Marcos Castro (Víctor Manuel Mendoza)
• Brady's orders: in exchange for gold ore and pesos, he was to pick up a shipment of illegal guns across the Rio Grande border in the town of Puerto, Texas from general store owner Ben Sterner (John Banner); ultimately, when the guns were sent into Mexico, they disappeared (presumably stolen by the Apaches) and never reached General Marcos
• Brady's relationship with his beloved horse - named Lagrimas -- "a Horse Called Tears" (a metaphor for Brady's life) - an Andalusian black horse gifted by the Governor; in the film's opening, when the horse bucked Brady after being spooked by tumbleweed during his entry into the Texas town, Brady broke his right leg and was forced to recuperate for three months
• while recovering, Brady's association with Texas Ranger Captain Rucker (Albert Dekker) who wished to recruit him into the Rangers (and forget his troubled past years earlier when he murdered the man who killed his father), and humorless Maj. Stark Colton (Gary Merrill) - leading a "Buffalo Soldiers" battalion of black troopers; Brady was urged to join together (along with Castro's forces) in a coordinated campaign to eliminate the raiding Apaches who would attack Texans and then hide back in Mexico
• the sequences of Brady's growing romantic interest in cold-hearted Major Colton's sultry, wistful and unfulfilled wife Helen Colton (Julie London)
• the film's major turning point -- Brady's lethal self-defense encounter with drunken, roughneck ranch hand bully Barton (Chuck Roberson) - following a quick-draw shootout, Brady was forced back across the border into Mexico to resume work for the larcenous Castro brothers involved in a deadly power struggle; he was pursued by the forces of Castro, Marcos, and the Apaches
• the scene of the lingering death of severely-wounded Major Colton, who offered his wedding ring to Brady with his final wish: "If I don't survive the charge, please take her this ring"
• following the death of Helen's husband, the most crucial dialogue between Brady and Helen toward the film's end, when he told her that what they felt for each other wasn't wrong - she challenged him to cross the river from Mexico into Texas at Puerto to be with her for the future:
  Helen: "It's wrong. What we are and what we did, and God help me, what I'm feeling right now for you, with my husband not even in the ground yet. We've said everything. There's nothing more to wait for, there's nothing more to know. If you want me, Martin, you'll have to come and get me. You'll have to cross the river. Thank you for bringing this (the ring)." Brady: "Look, what we did, maybe that was wrong, but not what we feel." Helen: "What a pity then, that life is what we do and not just what we feel."
• Brady's redemptive return to Texas - in the film's final few minutes, his horse was shot from under him by an assassin (he quickly dispatched with the killer), and was forced to mercy kill his severely-wounded horse (off-screen); Brady set aside his six-shooter gun, gun belt and hat next to his dead horse, and walked on foot toward the Rio Grande, to cross and enter back into Texas - to join Helen and start life anew