This was an unjustly passed-over entry to the Sergio Leone catalog of vaguely psychedelic, politically subversive "spaghetti Western" films like The Good, the Bad and the Ugly. This one takes place in Mexico during the Revolution, toward the end of the Old West, when the wagon trains were being replaced by armored cars and rolling artillery. Gatling and Maxim guns had entered the scene, bringing a new lethality to human encounters. Rod Steiger is hopelessly miscast as as the Mexican patriarch of a family of apolitical bandits. His Mexican accent is as bad as Dick van Dyke's Cockney accent in Mary Poppins.

We meet James Coburn, equally miscast as an Irish revolutionary with enormous, shockingly white teeth, in Ireland as his blissful Jules and Jim-esque love triangle with his best friend and their best gal ends in tragedy, as he is forced to kill his best friend and a bunch of English policemen with a submachine gun after his friend betrays him and the revolution.

There are a lot of terrible things about this movie, particularly the casting. But it has two things that make it essential:

1: it's one of the best movies about revolution and its causes, and who pays the price for it, I think ever.  Some of the dialog is up there with Billy Wilder, like Coburn and Steiger's conversation about Bakunin, where they hash out the ironies of relatively well-fed intellectuals feeding their less fortunate brethren into the maws of death in the name of equality. Steiger's Bandit Dad is the opposite of a desktop revolutionary, he has too many children to have time for that, and while he is tricked into becoming a "Hero of the Revolution," it ends in being the worst thing to ever happen to him.

2: The score, by Ennio Morricone, it's comedic, it's romantic, it's bizarre, it's flatout heartbreaking beautiful at times. 

It also has great if sometimes excruciatingly cruel cinematography and Leone's enigmatic direction. I highly recommend it, and pay attention to the score!