TONIGHT THE children will be out, pretending to be demons. The whimsical traditions of trick or treat, masked mischief, and ritualized mayhem are a way of dealing with a dark mystery.
The delightful fright of the haunted house and its spooks initiates youngsters into the macabre realm of mortality. Costumes teach that deception is part of life. The threat at the door implicates even the innocent, who happily enact the abandonment of morality. The figure of the witch is emblematic because this holiday makes a joke of scapegoating murder. Play is never more serious than on Halloween because what the mockery confronts is nothing less than evil.
What is evil anyway? The myths of the devil, a snare-layer existing apart from humans, are well established, from Lucifer to Satan to Cruella. Their legends promote the notion that we descendants of Eve are at the mercy of a wicked enemy whose attacks are from outside. When we personalize that enemy and identify it, we can launch a counter-attack. The battle is what our children enact tonight. Smashing pumpkins is a version of witch-burning; if we like such violence it is because it leaves us feeling purified. Nothing sanctifies the self like condemnation of the other.
But there is another way to think of evil, finding it in the juncture between individual freedom and social context. The story of Genesis posits the malevolent serpent, but what ruined Paradise was not the serpent but the option made in its favor by Adam and Eve. What follows such choice is always unforeseen, but its dynamic is inevitable: Choice leads to consequence, which leads to new and graver choice, which leads in turn to yet graver consequence, and so on. A train of action-reaction is set in motion that quickly outpaces the ability of any one person to slow it.
This phenomenon can take the form of the ''grooved thinking" of a bureaucracy or of the ''institutional culture" that trumps even the good intentions of those who operate within it. Every human choice is made inside a rushing current of prior choices, and the pressure is not good.
Saint Paul spoke of the ''wiles of the devil," but his defining metaphor for evil was systemic, not personal. ''For we are not contending against flesh and blood," he wrote, ''but against the principalities, against the powers, against the world rulers of this present darkness." For Paul, the enemy was not fallen angels, but ''sovereignties" which are hostile to humanity. He was talking about Roman tyrants and an uncaring imperial bureaucracy. He was talking about politics.
The clearest instance of this phenomenon today is unfolding in Iraq. ''Wars generate their own momentum," Robert McNamara once wrote, ''and follow the law of unintended consequences." George W. Bush must be held accountable for the consequences of his fateful decisions, from the 2,000 dead Americans to the American embrace of torture to the igniting of a clash of civilizations. But the ease with which the United States embarked on Bush's unnecessary and illegal war -- with huge popular, political, and pundit support -- was evidence of an already established momentum that predated Bush, and even his father.
Truman, Eisenhower, Kennedy, Johnson, Nixon, Carter, Reagan, and Clinton all kept the malevolent current flowing, if despite themselves. Bush simply stepped into it. An unprecedented American momentum toward war was unleashed in the 20th century, its destructive energy fueled by the heat of an unchecked nuclear arsenal. That momentum defines the nation now, and, for the first time in history, threatens the very earth. The principalities and powers are us. In the name of the fight against evil, good people established the ''sovereignty" of a militarized culture, laying bare the darkest mystery of all: What we construct to oppose evil involves us in it. Having armed evil with the nuclear bomb, we have made evil more sovereign than ever.
If only there were a devil to exorcise or a witch to burn. If only there were an axis of evil to oppose. Well, there is Saddam -- never mind that the crimes for which he is being tried drew winks from Washington. There is Iran with its blood curdling anti-Semitism -- never mind that its nuclear agenda is set by US policy. Like children reading costumes, we know the wicked from the good. We make our threats, seize our booty, and name the enemy, not thinking that we ourselves have become the world's. For America's children, this is play. For their nation, it is war. Trick or treat.
James Carroll's column appears regularly in the Globe.