Prime Minister Pierre Trudeau and this country's nine English-speaking premiers have traded Canada's first independent constitution for a troubled future.
The agreement, reached here last week after four days of grueling bargaining between Trudeau and the 10 provincial premiers, means that the prime minister will achieve his lifetime goal of giving this former colony a constitution free from all British control.
But it dangerously isolates Quebec, Canada's only French-speaking province, and has set the stage for a crucial test of national unity.
Quebec Premier Rene Levesque, who is determined to force an independent future for his province, refused to sign the agreement and warned that the ''consequences could be incalculable'' for Canada.
In a harshly worded speech to the prime minister and the other premiers, Levesque warned that his government would do everything in its power to ensure that the new constitution is not imposed on Quebec's 6.5 million people.
''Never will we accept that our traditional and fundamental powers be removed without our consent,'' he said. ''We will take all means left to us to ensure that does not happen.''
Levesque refused to disclose his strategy, but the federal government expects he will take advantage of the latest clash between English and French cultures to call another referendum on independence.
In May 1980 Quebeckers voted 60 percent in favor of the Canadian status quo after Ottawa promised to renew federalism to make it more attractive to Canada's French minority.
But Levesque now argues that the federal government has broken its promise and forced his province back into its traditional English ''straitjacket.''
The agreement provides for patriation from Westminster of the British North America Act, the British statute that has governed Canadian affairs for 114 years, and an amending formula for future constitutional change.
It also includes a weaker version of the controversial federal charter of human rights and freedoms that the provinces had opposed on the grounds that it usurped provincial powers.
Levesque's refusal to sign the agreement centers on two points: (1) his belief that the federal government is unilaterally reducing Quebec's power, and (2) a clause that would force the province to provide English-language education for its 20 percent minority.
Trudeau referred to Levesque's opposition as ''the one sad note in this conclusion'' and said he hoped future negotiations would convince Quebec to sign the agreement.
''I am hopeful, that with good will, we will very soon be able to make this accord unanimous,'' the prime minister said.
But it was clear during the talks that the federal government isolated Quebec to obtain the required support of the western and maritime provinces.
Those provinces all won major economic concessions, which will ease strained federal-provincial relations, but Quebec lost the language argument as well as its veto on all future constitutional changes.
Although the federal tactic was successful, it made another showdown between Ottawa and Quebec inevitable.
Justice Minister Jean Chretien, the prime minister's Quebec lieutenant, said it is Levesque's prerogative to call another referendum and made it clear that the federal government is prepared to take its case to Quebeckers.
That case was considerably strength-ened by last week's agreement.
In a move that surprised Ottawa, the other nine provinces agreed to provide French-language education where numbers warrant.
Trudeau plans to use that breakthrough to convince Quebec that the rest of Canada is anxious to protect French language and culture.
Levesque has already rejected that tactic as ''blackmail'' intended to force Quebec to protect the minority English culture there.
In spite of Quebec's angry opposition, the federal government is preparing to push the new agreement through Parliament as quickly as possible.