OTTAWA — Ottawa. -- In the summer of 1831, when Alexis de Tocqueville was making the journey which produced his great book on American democracy, he visited French Canada, the experience producing in him the sober conclusion '' . . . that the greatest and most irremediable calamity that a people can suffer is to be conquered.''
Leaving Canada to resume his travels in the United States, he wrote: ''In Canada there is a great role to be played, at once noble, honorable and dangerous. It is that of a man who dedicates himself entirely to the French-Canadian people, living for their interests, exciting their passions in order to preserve their existence, making himself the disinterested and free counsel of all, mingling his life wholly with theirs, the adversary of the government each time an occasion for attack presents itself, obtaining a thousand concessions from those in power, always asking for more and, when the passions of the master and his subjects are aroused, when the people are enlightened as to their true interests, proclaiming loudly the words independence and liberty!''
No single such man was to emerge. But the cumulative experience of a century and a half of French-Canadian history has finally produced a Quebec on the verge of proclaiming its liberty, as Tocqueville wanted and thereby destroying that Canada of ''two founding nations'' which has existed since the 18th Century.
Little more than a year remains. If no new constitutional agreement is reached between the English-speaking provinces and Quebec by October 1992, Quebec's government says that it will conduct a referendum on sovereignty and act on the outcome.
Canada's Prime Minister Brian Mulroney has made his former foreign minister, Joe Clark, minister of constitutional affairs with the charge to search for a solution acceptable to Quebec and to the English-speaking provinces, a solution no one else has yet found.
Many in the English-speaking provinces say the Quebeckers merely are ''obtaining a thousand concessions'' by threatening to leave the federation. This may prove true; but then it may not. They also say that Quebec can't survive alone because those economic projections which say that it can presume that Quebec would continue to have access to all the markets of the North American Free Trade Zone.
But English Canada would have nothing to gain from breaking up the trade zone to punish a sovereign Quebec, and certainly the United States would have no reason to do so.
Quebec, in fact, has a plausible theory of independent survival. The rest of Canada does not.
Quebec now is an industrial success, profiting from the free trade agreement, which soon may be extended to Mexico. It has an energetically independent cultural life. It produces more original television programs than France. It exports pop stars to the Francophone world. It has a vigorous literature.
It is in no danger of cultural takeover by the U.S. That is not the case for the rest of Canada. (Nor is it the case for French Canadians who are not Quebeckers. Quebec's population is about a quarter of Canada's, but French-speakers are 30 percent of the Canadian total.) France is no threat to Quebec's autonomy. For the French, Quebec is as distant and exotic as Cajun Louisiana. Quebec could survive.
But what is English-speaking Canada if there is no Canada? Saskatchewan, Manitoba, and Alberta might as well be part of the western United States. British Columbians have more in common with Oregon and the state of Washington than with Eastern Canada. The objection to former Prime Minister Pierre Trudeau's project for a bilingual Canada was that western Canadians resent being not only taught but governed in a French language for which they have no use.
British Columbia's Vancouver Island is rapidly substituting itself for Hong Kong island, as investment and investors prudently abandon Hong Kong to the Communist rule that will be imposed in 1997. Cantonese must seem to British Columbians a more sensible language to learn than French.
That leaves Ontario, the old and poor Atlantic provinces, the Northwest Territories and the Yukon. The prospect after 1992 is of Upper and Lower Canada Ontario and Quebec reemerging much as they existed in the 19th Century, before federation in 1867. (Modern Canada, with the western provinces included, has only existed since 1905, and Newfoundland joined the Federation only in 1949).
But why should it have come to this? The Canadian provinces have an autonomous North American history older than that of the United States. Jacques Cartier planted a cross on the Gaspe Peninsula in 1534, and permanent settlement began in Nova Scotia in 1605.
Canada's autonomous existence is due to the fact that its settlers chose not to be part of the United States. Why should a society with North American roots so profound, and so distinct from those of the United States, now abandon itself?
The answer, of course, lies in what Tocqueville wrote. Today provides the culmination to a two-century struggle between the conquered and a conquering people.
But history does not have to be a fatality, and what separates Quebec from the rest of Canada is much less than what separates it from the rest of the world. Both French and English-speaking Canadians would be diminished were Canada to fail. That, however, may be discovered too late.
William Pfaff is a syndicated columnist.