WASHINGTON -- Opening in theaters Friday, a motion picture called "September Dawn" depicts a brutal American massacre that has been forgotten. On Sept. 11, 1857, in Utah Territory, Mormons slaughtered more than 120 California-bound settlers from Arkansas. Retelling at this time the 9/11 carnage of 150 years ago does not help Mormon Mitt Romney's presidential campaign.

The basic facts about the Mountain Meadows Massacre are not in dispute. Mormons mobilized Paiute Indians, accompanied by Mormons disguised as Indians, to attack a peaceful wagon train. The settlers beat off the attack but were left short of food and ammunition. They disarmed themselves at the request of Mormons who said they would lead them to safety but instead turned on the settlers, murdering every man, woman and child above the age of 8. All that is in doubt historically is whether this was ordered by Brigham Young, president of the Mormon Church and territorial governor of Utah. "September Dawn" says he was responsible, and the church denies it.

Today's Mormons, including Romney, cannot be blamed for these events. Nevertheless, the candidate has followed the church's example in ignoring this movie. Romney will not comment on "September Dawn" and indeed will not watch it. That follows his decision not to defend his Mormon faith or actively fight religious bias that has impeded his candidacy.

I attended an April 11 screening of the movie at the Motion Picture Association of America headquarters in Washington, hosted by its lead actor: Academy Award-winner Jon Voight (who plays a fictional Mormon bishop). A conservative, he said this was no hit against Romney. "I didn't even know he was running when we began this," Voight told viewers after the screening. But he said this terrible story is important considering America's war against terrorists.

Indeed, Brigham Young -- played by the British actor Terence Stamp -- is portrayed in the film as a 19th-century Osama bin Laden. Calling himself a "second Muhammad," he insists on the "shedding of blood" by "gentiles." He is seen fighting the United States, which was sending federal troops to Utah.

The church always has accepted Young's plea that he had nothing to do with the Mountain Meadows Massacre. But Voight is certain that he did, based on research for the movie. "If any miserable scoundrels come here, cut their throats," Young said in his "Blood Atonement Sermon" (which concluded that he would not fight "unless they come upon us and compel us"). The movie's researchers found in the church archives a generic threat against interlopers: "I will loose the Indians on them, and I will slit their throats from ear to ear."

In response to this column's inquiry, a Mormon Church spokeswoman in Salt Lake City Wednesday said: "The weight of historical evidence shows that Brigham Young did not authorize the massacre." She added that "the church has no comment on the 'September Dawn' movie."

John D. Lee, Young's adopted son who led the massacre, was executed by a firing squad 20 years after the killings -- the only person punished. "I have been sacrificed in a cowardly, dastardly manner," he said after his excommunication by the church and his conviction. In his autobiography, he said the attack was planned "by the direct command of Brigham Young."

I knew no Mormons growing up in Joliet, Ill., and my first experience with the church was watching the 1940 film "Brigham Young." It depicted the original Mormon settlers in Utah as persecuted and peaceful, and Young as prudent and wise. When some Mormons complained then that Young came over as vacillating, church president Heber J. Grant said of the movie: "I endorse it with all my heart. This is one of the greatest days of my life." He knew it could have been much worse.

Mitt Romney surely is not responsible for what kind of man Brigham Young was, but that question hurts his candidacy. Romney has been described by many Republican insiders as the perfect candidate: magnetic, smart and with an excellent record as an executive. His greatest liability has been religious bias against him. He has never seized this issue, thinking it so wrong-headed that it will go away.

Similarly, he has rejected efforts by the producers of "September Dawn" to reach out to him. I made three attempts without success to get his views of the movie. Neither watching it nor condemning it, he may just hope that Americans will not include this bloody tragedy in their spring and summer viewing.