Let us speak very calmly of this.

When was it conceded, explicitly or implicitly, that there is a right of secession from the Canadian federation? The one point on which Jacques Parizeau and Jean Chretien agree is that Canada may not use force to preserve itself. What are they going to do, jokes Parizeau, send troops down the Boulevard Rene Levesque? I'm a democrat, Chretien says, to show he need not say it, I would never seek to hold Quebec against its will.

Oh? And why is that exactly? All through this summer's Oka crisis, the contrast was noted: If Quebec may declare itself sovereign, why not the natives? But turn the question around: If natives may not, why may Quebec? However it may be festooned with the legitimacy of a popular vote and appeals to the right of self- determination, we must be clear on one point: Separation is an illegal act, which would destroy one of the world's great democracies.

Nowhere does our Constitution provide for the right of secession. This is no accident: It could not do so. No federation can be constructed on the basis that its members may come and go as they please, that they may refuse to obey its laws when it suits them. Not only would the integrity of the state be thus undermined, but so would the stability of the social order itself. Sovereignty is indivisible, as the atom. It may be fused with others - but split it then, and you release forces of incalculable destruction.

Yet it is not only acknowledged, but celebrated, that Canada, should the occasion arise, would not act to enforce its sovereignty in Quebec. It is taken as a sign of our supremely democratic values that we would acquiesce in our own demise. We wouldn't ''send in the troops,'' of course, nor am I suggesting we should. But let us not confuse expedience with principle: This is strictly a matter of numbers, and of nerve.

We would not use force because by then it would already be too late: Canada's legitimacy would be so far gone as to be irretrievable. But in part this prophecy is self-fulfilling. The failure of our nerve occurred at the moment the legitimacy of secession was conceded. The separatist case rests on nothing loftier than this: that they have more nerve than we do. They will take power because they can.

But suppose there were a legitimate right of secession. This implies that Confederation was a compact between sovereign states. Revocation of the compact, therefore, would restore the borders of the state wishing to secede to those prevailing before Confederation. There is no conceivable principle by which a sovereign Quebec would retain the lands granted to it by the Dominion in 1898 and 1912.

Those territories, covering two-thirds of modern-day Quebec, were granted to Quebec as a province of Canada. They were not given as going-away presents. Yet not one in 100 Quebecers who support sovereignty does so in the belief that an independent Quebec will not control, for example, James Bay. So what will we do when the government of Quebec insists, as it will, on its present borders? Will we have the nerve to enforce our sovereignty then?

The principle of self-determination is not absolute, nor is it even well-defined. A group of people does not have the right to govern itself, and to detach itself from another, simply by virtue of declaring it. If there were such a right, then we should be consumed by an endless series of secessions, of province from country, city from province, borough from city, and so on.

It is conditional, rather, on the purpose to which such sovereignty is to be put: on its conformity to the higher principles of freedom and democracy, in comparison to the existing arrangement. That Lithuania should seek freedom from a totalitarian Soviet Union is one thing; secession from a democratic federation smacks more of tribalism.

The criterion by which the self-determination of Quebec should be judged is likewise whether it is more likely to advance those universal human values than Canada. Nothing in the rhetoric of today's Quebec nationalists should lead us to believe that. We need not conjure up extreme visions to say that at the margin, Quebec is likely to be less free than Canada: People do not seek control of the powers of the state who do not intend to use them.

We must, therefore, be prepared to assert the moral hegemony of the Canadian idea - that a united Canada and a divided Canada are not simply alternate living arrangements, but that one has greater moral claim than the other. Without such sense of purpose, we cannot summon the nerve to confront those who would wreck our nation.