Scarcely four days later, and already the death of Meech Lake has brought at least five bits of good news. If nothing else, the risk of Jean Lapierre becoming a federal cabinet minister has been closed. But there's more.

The C$, having shaken out all but the most irremediable optimists by June 23, has shot up almost half a cent, opening the way to lower interest rates. The federal government has regained the power to name more senators if necessary to force the goods and services tax through the Upper House. The Hibernia oil megadoggle may be dead, Tory vindictiveness at last effecting what plain economic and environmental sense has long demanded.

Best of all, we are never ever going to have another first ministers' conference on the Constitution. Robert Bourassa has succeeded, where Pierre Trudeau, Clyde Wells and the rest of us who persist in such quaint notions as Canada and responsible government could not, in killing executive federalism.

The premier's statement that henceforth Quebec would deal only bilaterally, with Ottawa or the other provinces, has excited a great many predictions of the ''one thing is certain, Canada will never be the same'' variety. This is undoubtedly true: If there is anything Wells and Bourassa agree upon, it is that no one wants Canada to stay the same.

But one cannot let pass without comment the gross overconfidence of Quebec nationalists, who boast that they alone will now determine the future of Quebec and of Canada. Apparently they believe Quebec will simply unveil its demands, whether for special status or sovereignty-association, and the government of Canada will accept them. I hate to spoil a really great party, but these people are kidding themselves.

OPINION POLLS

First, they may well overstate their support, on the basis of a few opinion polls taken in the heat of recent months. With Meech Lake no longer stoking the fires, and with a spokesman for federalism back in the province after six years, nationalism may have peaked. The more intense a surge in popular passions, the shorter it tends to be.

Second, whatever the present government may be prepared to hand over to Quebec, we are still governed by a Constitution which makes no provision for a wholesale abdication of federal authority, let alone separation. The world - world capital markets in particular - takes a dim view of unilateral declarations of independence. So any change in Canada's constitutional framework will have to be negotiated with the rest of Canada.

In that context, it will rapidly become clear that sovereignty is not an option. Within Confederation, Quebec has always carried disproportionate weight, which most people of good will do not begrudge it, given its peculiar circumstances. But once it declares its intent to leave Confederation, it loses all such leverage. At that point, raw numbers come into play, and separation could be made as costly as we wish. There is no question of our moral authority: the principle of self- determination can be invoked in the name of the Canadian nation as much as of Quebec.

Certainly the nationalists have been encouraged to underestimate these costs by the almost complete collapse of will apparent among Canada's political class. Indeed, it is now clear significant support for Meech Lake came from those who, far from deluding themselves it would help to unify Canada, knew it would hasten a dissolution they viewed as inevitable. They only hoped the deed might be done without too much mess.

Nations, if they wish to survive, do not try to reduce the costs of their dismemberment. There are present, within any nation, groups which might secede. It is not realism, but self-deception, to think a union can be held together by saying ''yes'' to everyone. At some point one must say ''no.'' And if that is to be credible, there must be real barriers - psychological, procedural, economic - to separation. If the prospect is to deter, it should be messy.

Any nation worthy of the name must make it clear that, however sensitive it may wish to be of minorities within it, it will not acquiesce in its own destruction. Jacques Parizeau knows this. The PQ leader, meeting with Quebec native groups recently, offered to grant them constitutional recognition in a sovereign Quebec. But there was to be no question of secession.

Nations, as much as humans, do not typically lack a will to live. If those who lead us now do not have enough fire in their belly, then we will find others who do. Whatever change comes to Canada will be on Canada's terms.