The Supreme Court has given a unanimous rebuke to the Conservative government's attempt to transform the Senate into an elected body without provincial consent, a ruling Prime Minister Stephen Harper said leaves him with little choice but to abandon his long fight to reform the Red Chamber.

Mr. Harper had said he wanted to democratize the Senate or kill it, but the court ruled that his government could do neither as it proposed to do – unilaterally create a system of elections and nine-year term limits, or abolish it with the approval of seven provinces with half the population. The court said abolition required unanimous consent, while elections and term limits would need at least seven provinces with half the population on board.

"The Senate is a core component of the Canadian federal structure of government," said the ruling, which was written in the court's name rather than by an individual so it would be seen to carry the court's full weight. "As such, changes that affect its fundamental nature and role engage the interests of the stakeholders in our constitutional design – i.e. the federal government and the provinces – and cannot be achieved by Parliament acting alone."

Story continues below advertisement

The court was responding to a request from the government for a legal opinion on whether it could go ahead with the proposed Senate Reform Act. Mr. Harper called the rejection "a decision for the status quo. A status quo that is supported by virtually no Canadian."

The Senate is embroiled in a controversy over expenses, and provincial legislatures in Manitoba and Saskatchewan have called for its abolition. But the country has no appetite for "a bunch of constitutional negotiations," Mr. Harper said. "We know full well that there's no consensus among the provinces, there's no willingness to reopen the Canadian constitution." Some Conservatives previously called for a referendum on Senate reform, but Democratic Reform Minister Pierre Poilievre said the government is not planning one.

Some premiers, such as Ontario's Kathleen Wynne and Prince Edward Island's Robert Ghiz, say they are open to discussions on Senate reform. But Saskatchewan Premier Brad Wall said the ruling gave a de facto veto to every province over meaningful change, and means "Canadians are stuck indefinitely with an unelected, unaccountable upper house, a principle feature of which is a representational bias against western Canada." In any event, such discussions could open a Pandora's box of issues around aboriginal rights and the inclusion of Quebec.

Besides, most provincial governments do not really care enough to make it worth the effort, said Roger Gibbins, a senior fellow at the Canada West Foundation, a think tank focused on the West. "I just don't think anything's to be gained by the federal government spending more political capital trying to round up the provinces for something they're not really that interested in."

He said the ruling gives Mr. Harper a chance to lift the "albatross" of Senate reform from his party's shoulders, and to tell voters: "We gave it our best shot. Senate reform will be something for our children and grandchildren to tackle. We're leaving the field."

Mr. Harper was advocating Senate reform as far back as the late 1980s, when he was a policy adviser to the Reform Party. As Prime Minister, he stalled on filling vacancies while he introduced legislation mandating term limits and elections, but when those bills did not pass, he made partisan appointments. Three of the Conservative senators he appointed have been suspended over their expense claims.

The ruling was the Harper government's fifth unanimous or near-unanimous defeat at the hands of the Supreme Court in the past month, all involving major files, such as the appointment of a new Supreme Court judge and the tough-on-crime agenda.

Story continues below advertisement

The Constitution says explicitly that changes to the method of selecting senators, or to the Senate's powers, require the approval of seven provinces with 50 per cent of the population. But Ottawa argued that the reform act would not legally change the selection method, because the prime minister could reject the election winners.

The court replied that the argument put "form over substance," and that the constitution has an "architecture" in which each plank must not be looked at on its own, but as part of a coherent whole.

Mr. Russell said the court had set out basic principles of Canada's constitutional democracy. "It was almost like giving the alphabet to first-graders." The court's message was that "you don't approach the Constitution as if it was a lawyer's contract. You approach it as the framework for a great nation."