Some acts are just incomprehensible. Violent crime offends almost all people, but even as we condemn such acts, we can usually construct a plausible string of circumstances that explains such behavior and puts it in some context. Some crimes are inexplicable, beyond the imagination of all but the most twisted minds.

The murderous rampage by Mr. Anders Behring Breivik falls in the latter category. There is nothing that can explain the tragedy he has inflicted on Norway or cast it in anything except inhuman light. Mr. Breivik, 32, is a middle-class Norwegian who led a relatively quiet life — until last week. He joined the anti-immigrant Progress Party, Norway's second biggest party over a decade ago, paying dues from 1999 to 2004.

Earlier this year, he moved from Oslo to the countryside, where he established an organic farm. It is now believed that he did that to gain access to large quantities of fertilizer that he could use to build a bomb.