Warning: Minor plot spoilers

"Angels & Demons" is an exercise in Catholic-bashing that falls short because author Dan Brown doesn't know enough about Catholicism to create a convincing distortion of it.

I'm not Catholic, but I've covered the church for nearly 30 years, including the 2005 papal election. Although this movie gets many visual details right, its version of church teaching, history and governance is fiction.

The movie's most faithful Catholics are villains who believe they have the right to murder for their faith. Initially, I thought it attempted to be evenhanded in its bigotry, since avowed atheists were portrayed as sadistic, homicidal sociopaths. But it turns out -- and our film reviewer forbade me from detailing the silly ending -- that's a sham.

As the movie begins, a pope has died and four cardinals have been kidnapped by "the Illuminati," a secret society allegedly dating to the Renaissance that supposedly vowed revenge on the church for the persecution of scientists. The real Illuminati were freethinkers in 18th-century Germany, long after the deaths of Bernini, Galileo and others who the movie claims belonged to them.

The group dissolved before 1800, although some far right-wing conspiracy theorists claim that it endures and is plotting to rule the world via the Skull and Bones Society at Yale University.

The plot turns on the idea that the Catholic Church is opposed to scientific research. In fact, the Vatican sponsors a world-class observatory and conferences on science and ethics.

But, as if the church didn't have its own scholars, the Vatican turns to Harvard "symbologist" Robert Langdon (Tom Hanks) to save the cardinals. Langdon can't read Italian and struggles with Latin, but apparently those aren't required for a doctorate in this nonexistent field.

A Vatican cop says, "If the Illuminati are in Rome, we will hunt them down and kill them."

The Catholic Church opposes use of the death penalty. After Pope John Paul II was shot, he immediately and publicly forgave his would-be assassin.

While devout Catholics commit sins of all kinds, the motive isn't to preserve sound doctrine. People who care about the sanctity of human life don't hire hit men to uphold that teaching.

Arriving at the Vatican, with human lives at stake, Langdon takes time to lecture church officials about the alleged castration of some statues in the 19th century. The statues are real, but the body parts were simply covered with fig leaves. Although Pope John Paul II had fig leaves removed from frescoes in the Sistine Chapel, the statuary ones remained because they couldn't be chiseled away without performing the very emasculation that Langdon decries.

Contrary to the movie's claim, there is no group known as "the preferiti" from whom the next pope must be chosen. The cardinals can elect any male human, as long as he's willing to become Catholic and be ordained a priest and bishop. The machinations in this conclave would be unnecessary in real life.

A central figure in the film is the camerlengo (Ewan McGregor), who performs important administrative duties after the death of a pope. But while church rules require the camerlengo to be a cardinal, the movie version is a young priest.

One of my longtime sources, the Rev. Thomas Reese, a Jesuit political scientist at Georgetown University's Woodstock Theological Center, was appalled to learn that Brown claimed to have used his book, "Inside the Vatican," as source material. That explains why the movie is accurate with some visual details -- such as stringing the papal ballots together with needle and thread -- but not why it gets major stuff wrong.

The cardinals don't burn ballots after dark, as shown in the movie, because they have returned to the Vatican hotel. The real cardinals could evacuate if there was a bomb, as there is in the movie.

"If they thought there was a serious bomb threat, they'd tell everybody that it's time for lunch, go back to your rooms. That wouldn't be a big deal," Father Reese said.

But the movie cardinals not only refuse to leave, they won't evacuate St. Peter's Square -- which is far more crowded in the movie than during the real conclave. The senior cardinal says of thousands of endangered visitors, "We all go to heaven."

I'm not sure I can count all of the ways that statement violates Catholic teaching. I once covered a papal Mass at which a far larger crowd was evacuated mid-liturgy due to lightning.

During the real conclave, the square swarmed with police. They could have evacuated it on their own authority.

Another priest I know was a guide in the archaeological excavations beneath St. Peter's Basilica, where a key scene takes place. This site is accessible by two stairways, and there is no manhole entrance as shown in the film. Father Jim Farnan, the tour guide, read "Angels & Demons" years ago because he got goofy questions from people who read the book.

It mangles the geography of Rome, he said, putting some famous sites far from their real location. Perhaps the silliest scene in the movie shows Langdon diving and swimming in the Fountain of the Four Rivers in Piazza Navona.

"That fountain is about 6 inches deep," he said.

One facet of the book that doesn't make it into the movie is the claim that the deceased pope had a child by artificial insemination in order to avoid the sin of sex with the woman he loved. For the record, that would only compound the sin, because artificial insemination is considered an unnatural act.

Ultimately the ignorance, lies and bigotry in the plot undercut the message of scholarship, truth and tolerance that it tries to promote.