This piece first appeared on Beliefnet in February 2002. Andrea Yates's murder convictions for the drowning deaths of three of her five children was overturned January 6, 2005 by an appeals court. The court ruled that a witness for the prosecution had given false testimony at Yates's original trial.

Months after their deaths, the five drowned Yates children still linger at the edges of our minds, like silent, patient ghosts. The whole tragedy is a mystery. We can't imagine how any mother could do such a thing. We can't understand why the shock of the first limp body didn't stop her from killing any more. We can't even picture how she was physically able to do it. Those maternal arms look so thin; how could she hold a squirming 7-year-old under water for all those endless passing minutes?

The whole scene is incomprehensible. The children, sad and silent ghosts, can't tell us how it happened. The deed appears methodical, irrevocable, and numb; it feels like it's all happening underwater.

For Andrea Yates, however, things were anything but silent. As we listen to her broken statements, it's apparent that she lived in a landscape that was jagged, shrill, and threatening. Cartoon characters told her she was a bad mother. Satan, who she says put a visible "mark of the beast" on her head, told her to get a knife and kill her firstborn son. Her lawyer points to these statements as evidence that Yates was insane when she murdered her children.

When we hear Yates say Satan commanded the awful deed, a cartoonish TV figure jumps up to mimic her words: the comedian Flip Wilson, dressed as his alter ego Geraldine, exclaiming, "The devil made me do it!" Some readers can recall how swiftly this catchphrase spread back in the 1970s. It was fun to proclaim, buoyantly and belligerently, that you hadn't really wanted to take that second piece of pie: "The devil made me do it!" It was funny because it was so transparent. Everybody knew you were just kidding; everybody knew the devil can't make us do things.

This is not the same as saying he doesn't exist at all; in fact, belief in the devil is rising. A 1992 survey by the Gallup Organization found that just over half of Americans thought the devil was real. When they returned to the question in 1995, 65 percent said yes. Two years ago a Harris poll upped the figure to 72 percent.

We may suspect he's there, but we're not sure what he does. Even among Christians the devil has no clear role. In Western Christian theology, the drama of salvation takes place entirely between Jesus and his Father, with no devil required. The explanation goes: human sin had put us impossibly in debt to the Father; only a perfect sacrifice could pay for these sins; Jesus' death on the cross made that sacrifice and pay that debt. In this story, the Prince of Darkness had little to do but stand around gesturing ineffectively with his colorful props.

In the first thousand years of Christian faith, Satan did have a significant role. The early view was that sin had made us captives of death. Satan, the "evil one," continually murmurs temptations to us, coaxing us to march on toward that destiny.

But Jesus, by the cross, gained entry into the stronghold of death. Then, by his resurrection, he broke it open and set the captives free. The Eastern Orthodox icon of the Resurrection depicts Jesus pulling Adam and Eve out of their tombs, up into the light, while Death lies chained in his own manacles in the dark pit.

This view of an active and powerful devil is rooted in the Gospels, where a large proportion of Jesus' healings are exorcisms, and believers are exhorted to steel themselves against demonic temptations and attacks. "We do not battle against flesh and blood, but against the spiritual hosts of wickedness," St Paul wrote, and St. Peter warned, "The devil prowls about like a roaring lion, seeking whom he may devour."

So if Yates claims the devil made her commit her crime, is she being truthful, or crazy, or crafty? If the devil is real, the murders must have thrilled him--but how could we say that he caused them? Yates certainly experienced raging mental illness, and that ancient enemy, no gentleman, may have been marauding in her weakness; the factors are impossible to disentangle.

Still, "the devil made me do it" doesn't hold water. The devil tries to make people do things all the time, but they don't have to. Temptation comes whispering, but "Resist the devil and he will flee from you," St. James wrote. People tell the devil "No" every day. Yates herself refused to kill the first time she was told to; she resisted that command for seven years. Why did she finally give in?

Why do any of us give in, when much smaller temptations come knocking? What happened on an immense and hideous scale with Yates is what happens in miniature with us, as each day we face tempting thoughts and accept or reject them. When we make temptations our own they no longer startle or offend us; we bring the thoughts in like house pets and caress them, and begin to experience their power to command. Soon they feel irresistible; they feel like our very own desires. We become convinced we have the right to do whatever we want, no matter who it hurts.

Any talk of Satan is bound to make some people feel alarmed, particularly those who hadn't previously considered that he might be real. But there's no need to hunt or to fear Satan. His power is showy but flimsy, broken by our mere refusal to go along.

The key to that resistance is self-knowledge. The early Christians were emphatic that humility was the greatest virtue of all, and that it alone would send Satan scurrying. It's no skin off his red nose if we don't believe he exists: all the better for his subtle plans. The devil doesn't mind if we fail to see him, but he relies on our failing to see ourselves.