“For Greater Glory” is a meandering, malnourished epic of a forgotten Mexican civil war, the one “after” the Mexican Revolution that made Pancho Villa famous. This period piece, partly financed by the Catholic Knights of Columbus, is about the Cristeros War, when Catholic priests and peasants took up arms against Mexico’s revolutionary government’s efforts to repress the Catholic Church.

It’s a preachy and violent movie aimed at the faithful, people who won’t grimace or roll their eyes at every character who declares, “God save us from these heathens!”

In 1920s Mexico, the leftist administration of President Plutarco Calles (Ruben Blades) takes Marx’s maxim that “Religion is the opiate of the masses” seriously. It goes after the influence of the Catholic Church. Like the Republicans in Spain, they see the Church, aligned with the conservative status quo, as a weight on the population. Calles introduces “reforms” and edicts ranging from the practical — taking church dogma out of the schools, especially science class — to the more alarming — mass deportations of foreign priests, violence against priests who refuse to leave.

A coalition of church officials and reactionaries left over from the losing side of the recent civil war rebels. They call themselves “Cristeros,” and the revolt rages off and on for years. Priests like Father “General” Vega (Santiago Cabrera) take up arms when priests such as Father Christopher (Peter O’Toole, moving in his death scene) are executed.

But as the revolt roils the country, the Cristeros see they need a leader. They turn to a frankly agnostic hero of the Mexican Revolution, General Velarde (Andy Garcia). For reasons both righteous and mercenary, he and his wife (Eva Longoria) realize that he can make a difference for the disorganized Cristeros.

Visual effects specialist turned director Dean Wright, working from a Michael Love (“Gaby: A True Story”) script, manages the combat scenes — raids on villages, trains — well enough. But he has no sense of pace, and has a hard time keeping the various factions distinct. And if he can’t keep them straight, what hope do we have? The film lurches between firefights and arguments over the dinner table as Garcia’s Velarde mulls over the offer to lead the Cristeros. He still cuts a fine figure on a horse, but it’s a generally dispassionate turn, not helped by the confusion surrounding Garcia’s performance.

Any movie set in a civil war or revolution is going to take sides, and like the Opus Dei-backed “There be Dragons,” set during the Spanish Civil War, this one certainly has. And church backers can be expected to attempt a little cinematic pushback for the way they’ve been hounded. But they need to make better, less laughably propagandistic movies.

And as with “There be Dragons,” the history itself is dodgy. The horrific excesses of a government determined to rein in a church thoroughly allied with the former ruling classes are documented, but there’s nothing about the Cristeros’ mass slaughter of rural school teachers who dared to teach Evolution.

If you’re tackling a subject this complex, you need to be more careful. You need to aim higher than this.