Democratic societies have a hard time dealing with extremists in their midst. The desire to show respect for other people's beliefs all too easily turns into denial: nobody wants to talk about the threat posed by those whose beliefs include contempt for democracy itself.

We can see this failing clearly in other countries. In the Netherlands, for example, a culture of tolerance led the nation to ignore the growing influence of Islamic extremists until they turned murderous.

But it's also true of the United States, where dangerous extremists belong to the majority religion and the majority ethnic group, and wield great political influence.