Canadians who value free speech – and let’s hope that is all of us – should be deeply troubled by Ottawa’s decision to tell Canada Post to stop carrying a fringe Toronto newspaper. Public Services Minister Judy Foote ordered the postal service to cease delivering Your Ward News, which has been accused of being anti-Semitic and pro-Nazi. Her “interim prohibitory order” gives its editor 10 days to appeal.

Those who have campaigned against the free paper are “ecstatic.” But consider the awful precedent this act of postal censorship sets.

If people who are offended by something that appears in their mailbox can complain and get it banned from the post, where does it stop? Can a pro-choice feminist block the graphic pro-life pamphlet that comes in the mail? Can a fierce pro-lifer ban a flier from an abortion clinic? Or consider the feelings of the victim of East European communism who gets a Marxist tract in the mail? Why should an agency of the government that her taxes support be allowed to introduce that propaganda into her home?

This is the trouble with just about all limits on free speech. Who says what is beyond the pale? Deciding to block child pornography or open incitement to violence is easy enough, because of the direct physical harm they can be shown to cause. After that, it gets tricky.

Someone must have the power to determine what is dangerous or odious speech and what is merely passionate expression. It is always a matter of opinion. The line is impossible to draw, the scope for abuse endless.

Even in democratic countries, authorities have often succumbed to the impulse to black out what they don’t like. Communist propaganda was blocked on the grounds that it threatened national security, erotica on the grounds that it undermined public morals. The postal system was once one of the main agents of censorship. A century ago, postal censors blocked mailed instalments of James Joyce’s Ulysses.

Your Ward News is not Ulysses. Its editor, James Sears, who has been known to style himself as Dimitri the Lover, told City News that Hitler is his second-biggest idol, after Jesus. He ends his e-mails “Expel the Parasite!” – all in capital letters, of course. The group that has been fighting him calls his publication a “neo-Nazi-rag” that “has been permitted to disseminate racism, homophobia, misogyny and anti-Semitism to as many as 300,000 homes in Toronto.”

If so, there are a couple of ways to fight back short of censorship. One is simply to toss Your Ward News where it belongs: in the recycling bin. Nobody is forced to read it when it comes in the mail. People like Mr. Sears thrive on the oxygen of attention. Ignoring him is the best revenge.

Another is to argue back. If his opponents feel his maunderings are too despicable to pass over, they can always denounce or refute him. It is always better to fight speech with speech than to gag the speaker.

It is a good time to remember these old lessons about how to handle troublesome speech. Free expression is always under attack to some degree, and the danger seems especially acute today. The little tussle over Your Ward News is part of a wider struggle.

Overseas, authoritarian governments from Moscow to Beijing to Cairo are cracking down on the right to speak openly without fear. Canadians got a small glimpse of their attitude when China’s foreign minister dressed down a reporter in Ottawa for daring to ask a question about human rights. At home, on university campuses and beyond, the tendency to take offence is stifling healthy debate and silencing dissenting voices.

Sometimes those voices can be obnoxious, but it won’t do to try to snuff them out. Ottawa has no business telling the postal service to censor the mail just because some people don’t like what comes through the slot.