The Magnificent Seven(1960), The Professionals(1966) and The Wild Bunch(1969)
SPOILERS for all three Westerns:
Three Westerns across the length of the sixties developed a "template" for historical contemplation, with the backdrop of the Vietnam War there for simile:
The Time magazine critic wrote of The Magnificent Seven in 1960..."the movie speaks to the bond that will always tie the strong to the weak"...and thereby bespoke of the American spirit of 1960 that would soon put American "advisers" in Vietnam to help "the people." This is not an ignoble goal, and in The Magnificent Seven, the seven gunfighters(four whites, one Creole, one half-breed and one Mexican) join WITH the Mexican villagers to fight off Calvera's small bandit army. One battle is all it takes to "end it."
Four of the seven get killed defending that Mexican farming village; The Magnificent Seven is realistic in suggesting that men who commit to battle know that some of them will live, some will die. But with "The Professionals" in 1966, things shift almost to "fairy tale reality": all four men on the team survive to the end, while killing scores of Mexican revolutionaries along the way.
As with The Mag 7, The Professionals posits four Americans sent south of the border to Mexico on a mission. But two of them have "history" in Mexico, having fought on the side of Villa in the revolution, and being committed to a cause. Thus does "The Professionals" start to bring the issue of war -- and of an ongoing struggle -- into the Western. Burt Lancaster's character says: "Maybe for all time its only been one battle: the good guys versus the bad guys. The question is: who are the good guys?"
This question would be asked forcefully three years later with Peckinpah's The Wild Bunch, which Lee Marvin(one of the Professionals) turned down among other reasons, because it reminded him too much OF The Professionals(Americans south of the border; the revolution; picking sides.)
Marvin -- a top successful superstar at the time -- was replaced with a better fit: aging, fading 50's superstar William Holden, who could gallantly lead his vicious Wild Bunch not only into the revolution...but into certain death for everyone. The young Mexican among the thieves is tortured and killed by the Mexican general "on the other side"; this allows the four suriviving white outlaws to kill every corrupt Mexican in sight in a final battle that was both a bloodfest of content and a marvel of cinematic pyrotechnics.
Still, by the end of the decade, the idealistic goals of The Magnificent Seven had plummeted down to the gutter-level survivalism of the Wild Bunch, who allow church-going innocents to get gunned down in the crossfire(shades of Vietnam's collateral damage) and who are as animalistic and savage as they are noble(in their final sacrifice.)
Some of the Magnificent Seven die; all of the Wild Bunch die(less one old man who is not there for the final battle.) The "fairy tale of survival" in between in The Professionals isn't very believable but is still enjoyable. Still, the films marched across an American decade and kept shifting the ground on what the role of Americans in foreign lands would be.
And they are all damn exciting Westerns, with great cinematography, great acting, and great lines.