The slaughter of 76 people in Norway by a man described as a right-wing extremist has focused attention on Europe's struggle to contain a growing resistance to cultural pluralism and accommodation for visible minorities, a conflict that must be won by the forces of toleration.
It is easy to dismiss the sensational attack as the work of a madman, but it is only the latest in a series of violent actions against minorities across the continent. Several European governments, moreover, have fuelled anti-immigrant prejudice with policies that stigmatize newcomers and their cultural practises. Most leadership groups in Europe, however, also acknowledge the importance of multiculturalism, while complaining about the slow pace of cultural integration.
Unlike Canada and the United States, which were settled and built by immigrants and which depended on immigration for growth, European culture was largely pure laine, or homogenous. Historically, they were Caucasians who spoke a national language, worshipped the same God, consumed the same food and wore identical clothing.
The only real outsiders, even if they had been roaming the cities of Europe for 2,000 years, were Jews, a hated minority and convenient scapegoats whenever a crop failed, the economy faltered or disease swept the land.
The colour of Europe started to change after the Second World War, most noticeably in Germany which was short of workers and opened its borders in the 1960s to Turkish immigrants. Over time, Germany and other European countries began accepting minorities from across Asia and Africa, as well as Roma from Eastern Europe.
Some Europeans felt threatened by the influx, while others claimed the newcomers were taking advantage of western hospitality, living off the welfare state and contributing little in return. The seeds of resentment and hatred were born, or reborn, with Muslims replacing Jews as the unwanted outsiders.
It has taken Canada and the United States hundreds of years to develop policies, laws and customs on respect for minorities, yet still there are occasional outbursts of intolerance, so it should be no surprise that Europeans are struggling today with the concept of multiculturalism.
But when German Chancellor Angela Merkel said last year that multiculturalism was a failure, she was not saying the idea was wrong, just that Germans had not been successful in welcoming newcomers. And German President Christian Wulff's comment that Islam was part of Germany, like Christianity and Judaism, showed that many leaders do get it.
Unfortunately, a significant minority across Europe do not. Populist parties opposed to immigration and cultural accommodation are gaining support. They are not advocating violence and many of their leaders are appalled by what happened in Norway, but their support for intolerance has created a toxic brew where slime can grow and thrive.
The worst of these extreme groups is trying to reverse the tide of western history and recreate nations based on race and religion, a trend that can only end in more violence if it is not checked. If the madman of Norway is not to win, Europeans must redouble their efforts to create open and inclusive societies that speak with a civil tongue.