THE shooting rampage on Sunday that killed six people and wounded three others at a Sikh temple in Wisconsin exposed the continued dangers of white power extremism in our midst. The shooter, Wade M. Page, was affiliated with a range of neo-Nazi skinhead groups, and during the last decade, he played in several prominent bands in the white power music scene.

Mr. Page’s neighbors said they were “stunned” that he could have done something so violent or have been connected to extremist hate culture. And yet that culture claims an estimated 50,000 adherents nationwide, far more than most people realize. The white power movement persists, and even thrives, but not always in the ways we think.

Popular stereotypes paint neo-Nazis as young, swastika-tattooed skinheads yelling obscenities about blacks, Jews, gays and other so-called enemies of the white race, usually surrounded by counterprotesters and the police. In some ways, we are comforted by such images, because they let us believe it’s easy to identify extremists and intervene when they seem threatening.

But the reality is more complicated. White power adherents are not typically “out” about their extremist leanings. They straddle the worlds of white power and mainstream society, often publicly playing down or hiding their extremist identities. In the past, this might have been a hindrance. But these days they thrive in what we call hidden spaces of hate, often online, where they gather to support one another and their cause.