From each election we draw two lessons: one about our future policies, and one about our present politics. From two elections, north and south of the 49th, what do we learn of democracy and government in North America?

The U.S. campaign is depicted as the first truly post-modern election - a campaign entirely about a campaign: advertising about advertising; press coverage about press coverage; influential polls taken on the influence of polls.

If the process is a sham, an observer might nonetheless take comfort in the policies to come: Bush or Dukakis, no major disasters. Readers of this newspaper might like the Republican's hard line on taxes and preference for markets, others might choose the Democrat's promise of clean government and industrial strategy, but none could summon much enthusiasm for the one or distaste for the other.

Meanwhile we in Canada tell ourselves great issues are decided in our own election. Our debates, it is said, were full of substance and detail. Our campaigns are marked by argument not image; and if the rhetoric gets heated, it is the passion of principle, not the cold logic of personal attack.

What fear we feel owes not to the process of politics, but its outcome in policy. Those against free trade fear the end of Canada, those in favor fear little less. Those who have no settled opinion must be the more unsettled for believing that the survival of the country is at stake. They can seek solace, it seems, only in the knowledge that democracy at least is secure.

SUBSTANTIAL DIFFERENCES

Is it? Is this ordering of concern and unconcern with respect to politics and policy correct? Perhaps Americans in fact have less to be concerned about in their process per se than the policies that have emerged. And conversely, Canadians have more to fear in the conduct of this election than in its direct consequence.

I will not dwell on the U.S. election, except to say that if you add it up, the two candidates actually expressed substantial differences, clearly marked, on a wide variety of issues: abortion, the death penalty, health care, farm support, weapons systems, taxes. One might not care for their positions, one might indeed be disturbed by the voters' choice, but it is difficult to argue the voters did not have a choice.

More important, for all the bitterness and bile, both sides in the campaign adhered to certain very basic ground rules of debate, which must be shared if democratic government is to work. Rules such as: you can ignore logic if you wish, but you cannot wholly pervert it, and when caught you must explain; you can imply your opponent loves his country less, but you cannot baldly state it, and when challenged you must back down. Small niceties, perhaps, but democracy is like diplomacy: without such conventions, discourse between enemies is impossible, and ''other means'' are pursued.

This is, I suggest, what is truly at stake in this Canadian election. It is a matter of comparative indifference to me which party forms the government. It is of grave but not surpassing concern whether free trade passes. But it is critical, above all else, that language and logic be preserved as the final referees of debate. This, more than anything, is why John Turner's campaign should be so deeply disturbing to anyone who cares about democracy.

It is one thing to whip up fear, or to play on emotions. In a way, that is fair game, if only by sanction of precedent. But by the extremity of his claims, drawing on such extraordinary fears, Turner has simply knocked logic out of the ring. It is as if a massive electromagnetic pulse had stunned the synapses of the nation.

With the circuits down, Turner can safely say anything he likes. He can campaign against free trade, while claiming to be for it. He can say the Free Trade Agreement binds us forever, while mocking it for being cancelable. He can swear devotion to multilateral bodies like NATO or GATT, while deserting our commitments to them. He can claim our social programs at one and the same time raise and lower costs for Canadian business. He can warn that U.S. business will both move in and buy everything, and sell everything and move out.

He can even attack with his opponent's weapons. He can decry the lack of an abortion law, when it was his own law that was thrown out. He can describe the U.S. in the most hideous terms, suggest it plans to take over and denude our country, and accuse the Tories of anti-Americanism. He can vow to wipe out a whole category of taxes, pledge to increase spending by $27 billion, and decry the Tories' record on the deficit. That's not simply illogical. It's the annihilation of logic. It's dada.

A mere demagogue says, I'm against taxes, or I'm for protectionism. Turner is beyond demagoguery. He has invented dadagoguery.