A larger principle is at stake here, extending beyond immigration: the importance of vigilantly maintaining a distinction between political opinions and the people who hold them. It's hard enough to defend your own beliefs without also taking responsibility for the character, behaviour, and ideological consistency of every loon who happens to share them.

Take my own conviction that America's federal government has grown unwieldy. To promote this perspective is now to be thrown in with the Tea Party, a loose affiliation of heavily Christian advocates who well earned a reputation as obstructionist and impractical in this summer's debt-limit crisis. For me, these are strange bedfellows indeed — often homophobic and anti-abortion. Even on the budget, Tea Party types are notoriously woolly about what programmes they would cut, and determined to ring-fence not only defence, but Medicare — whereas I would cheerfully trim the military and overhaul entitlements. Nevertheless, you can't talk smaller government in the US any more without getting lumped in with this belligerent, unrealistic rabble. Bingo, I'm guilty of idiocy by association.

Jocelyne Cesari, director of the Islam in the West course at Harvard, wrote about the Norway massacre, "The distinction between legitimate ideas and illegitimate violence is naive and politically dangerous." I beg to differ. Legitimate ideas need protection, and questioning our right to air them is what's politically dangerous. Even morons can latch on to positions that knowledgeable people could justify. What's wrong with murderers is that they murder, not that they hold the wrong views.

We cannot allow lunatics, sociopaths, or people who hold a constellation of opinions, including some that are overtly unpalatable, to co-opt whole political viewpoints for which more well adjusted or less ideologically encumbered citizens could make cogent, persuasive arguments. Breivik's own lawyer claims his client is insane. Letting a man like that directly influence public policy would be as barking as Breivik himself.