It's not easy making major changes to a Canadian institution like the Senate. Just ask former B.C. premier Bill Bennett, former Alberta premier Peter Lougheed, Reform Party founder Preston Manning and former prime minister Brian Mulroney. Former prime minister Pierre Trudeau would agree, too, but for different reasons.

Now, Prime Minister Stephen Harper has his eye on remaking the upper chamber. It's a view he's held for a long time.

Overhauling the Senate requires constitutional reform, which means the government has to persuade seven provinces containing at least 50 per cent of the population that its plan is in the best interests of everyone. Making subtle changes to the way senators are appointed may be easier: the government believes it only needs to get a bill through Parliament.

After winning a majority government in May 2011, Harper is expected to introduce — for the fourth time — two bills to reform the Senate. That legislation would impose term limits on senators and set a mechanism for the provinces to elect nominees who would then be appointed to the Senate by the prime minister.

Senate appointments In all, 913 people have been appointed to the Senate since Confederation. Here's a look at the number of senators appointed under the different prime ministers. Sir John A. Macdonald: 91 Wilfrid Laurier: 81 Robert Borden: 62 William Lyon Mackenzie King: 103 John Diefenbaker: 37 Lester Pearson: 39 Pierre Trudeau: 81 Joe Clark: 11 Brian Mulroney: 57 Jean Chrétien: 75 Paul Martin: 17 Stephen Harper: 40 Source: Parliament of Canada

But at least one province — Quebec — has said it feels the proposed reforms affect its constitutional rights and that it plans to challenge the legislation in the courts.

Harper's previous efforts to pass the bills failed in the face of opposition in the House of Commons or a Liberal majority in the Senate. Now, however, the Conservatives have majorities in both houses.

Citing certain constitutional authorities, the Harper government is ready to argue that the proposed legislation doesn't require constitutional change.

And at least two provinces — Ontario and Nova Scotia — figure it's time to move beyond any talk of Senate reform and abolish the institution all together.

Creation of Confederation

The Senate, which came into being through the Constitution Act of 1867, was originally meant to act as a balance to the unchecked democracy of the House of Commons. But it didn't take Canada's first prime minister, Sir John A. Macdonald, long to decide that giving legislative veto power to a group of appointed wealthy men might not be in the best interests of the country.

The Senate's powers — but not its makeup — were altered so that the upper house could not defeat money bills or delay legislation unreasonably.

However, like the British House of Lords, senators would be allowed to keep their seats — and the salary that came with them — for life.

That changed in 1965 when the government of Prime Minister Lester B. Pearson passed legislation that forced senators to retire when they hit the age of 75. Anyone appointed before the legislation passed was exempted from the mandatory retirement rule.

Diverse agendas, similar goals

Calls for significant Senate reform began to be heard in the mid-1970s. Trudeau was making the case for constitutional reform, highlighted by a charter of rights. At the time, B.C.'s Bennett promoted a new model for the Senate, which he called the "House of the Provinces" in which provincial governments would choose senators to act as their delegates to the central government.

The idea had some support from both sides — but for different reasons. Trudeau, the advocate of a strong central government, felt that a senate made up of provincial representatives might actually weaken the authority of the provincial premiers.

At the time, Canada was undergoing significant demographic shifts. The populations — and economic clout — of Alberta and B.C. were growing much faster than Quebec's. Quebec still held 24 Senate seats while Manitoba, Saskatchewan, Alberta and B.C. held a combined total of 24.

By 1979, opposition to Trudeau's vision of a regionally enhanced Senate scuttled any notion of reform — as well as efforts to change the constitution. However, Bennett's proposal did serve to revive the idea of Senate reform.

Alberta was next to look at what to do with the Senate. Trudeau's National Energy Program had angered Albertans and then-premier Lougheed was looking for ways to keep Ottawa from intruding into his province's affairs.

Louigheed established a task force to look at ways of reforming the Senate and its recommendation was for the direct election of senators — and an equal number of senators for each province, like the American model.

The task force didn't get much attention in the rest of Canada, but an equal and elected Senate became a rallying cry for many Albertans.

Triple-E and Meech Lake

Then came the Meech Lake accord. It contained a provision that would have changed the way senators are selected. When a Senate vacancy came up, the prime minister would pick a name from a list submitted by the province where the vacancy arose.

As Meech was coming together, Preston Manning was turning his Western populist movement into the Reform Party. Part of its platform was a Triple-E Senate: elected, equal and effective, the latter meaning that an elected Senate would have close to the same powers as the House of Commons.

The Charlottetown accord contained more wide-ranging proposals for Senate reform.

Among the proposals were: an elected Senate — either by popular vote or election by members of provincial or territorial assemblies; six senators from each province and one from each territory; and guaranteed aboriginal representation in the Senate. In addition, the Senate could not defeat the government on a motion of confidence or block the routine flow of legislation relating to taxation, borrowing and appropriation. The accord also said senators should not be eligible to hold cabinet positions.

The reforms would never come to pass, doomed by the accord's rejection in the 1992 national referendum.

The constitutional squabbles, however, did not stop individual provinces from acting.

In 1989, a Senate seat became vacant in Alberta. The provincial government held an election among candidates who wanted the seat. Stan Waters won. A year later, Mulroney — who was still looking for provincial support in ratifying the Meech Lake accord — appointed Waters to the Senate.

Waters died a year later. His vacancy was eventually filled by Prime Minister Jean Chrétien the way prime ministers had always appointed senators.

In fact, it would be almost 20 years before another elected senator would join the chamber. Bert Brown, a longtime champion of Senate reform, took the most votes in Alberta's 2004 Senate election and was appointed in April 2007 by Stephen Harper.

Alberta and B.C. eventually passed legislation that provided for Senate elections. (The B.C. law, however, had a sunset provision and eventually expired.) Saskatchewan introduced legislation to that effect in November 2008.

The Harper era

The Reform Party — and its successor, the Canadian Alliance — continued to call for an elected, equal and effective Senate. But since the Alliance and the Progressive Conservative parties got together to form the Conservative Party of Canada in 2003, these calls have not been as loud.

In the campaign leading up to the January 2006 election, Harper promised to make the Senate a more effective and independent body.

After being elected as prime minister, Harper named Michael Fortier to a vacant Senate seat from Quebec — and then appointed him to his cabinet. (Fortier resigned his Senate seat on Sept. 8, 2008 to run in the federal election but he lost and returned to his law practice in Montreal.)

On May 30, 2006, Harper's government then introduced legislation that would limit senators to eight-year terms.

In December 2006, Harper said he would introduce the Senate appointment consultations act, which would allow government to consult Canadians on Senate appointments. "The bill will see voters choose their preferred Senate candidates to represent their provinces or territories," the government said in announcing the bill.

However, two years and one federal election later, the prime minister had not been able to initiate significant Senate reform. He named 18 new senators to be appointed by the Governor General to the upper chamber in December 2008.

After the May 2011 election, Harper named three defeated Conservative candidates to the Senate. Two of them had given up Senate seats to run in the election.