Some time ago, the leader of an opposition party stood during questioning and expressed regret that unelected senators thwarted the will of the House of Commons by rejecting a bill presented by a private member.

In response, the Canadian Prime Minister stood and expressed the government's view that the bill, despite being passed in the House of Commons, was full of serious flaws and was completely irresponsible.

This is how Stephen Harper justified the move by Conservative Senators to reject C-311 – the climate change bill sponsored and supported by the New Democratic Party and its then-leader, Jack Layton, which managed to pass the House because the Conservatives did not have a majority.

After nearly 13 years since the Senate's decision to kill C-311, the Senate began debate on the third reading of C-234, a bill introduced by a Conservative MP that would create a new exemption from the federal carbon tax for certain agricultural activities. The bill was approved in the House of Commons because there were not enough Liberal votes to defeat it.

The fact that the Senate has not yet approved the bill – and is even considering amending it – is causing some panic on the Conservative side in the House of Commons. On Tuesday, Conservative leader Pierre Poilievre proposed a motion calling on the unelected Senate to immediately pass C-234... as it was democratically approved by the elected House of Commons.

Poilievre told the House that the Prime Minister sent the carbon tax minister to pressure Senators to block the bill, in an undemocratic attack on the public’s right to determine who pays what.

It seems that one’s views on the rights and privileges of the Senate can depend on where one sits in Parliament at the time. And at least one major aspect of the Senate has changed over the past 13 years, as it now has a mind of its own.

The existence of the Senate is inevitable...

It is an undisputed fact that the Senate exists, although some may wish otherwise. The drafters of Canada's founding documents also made the Senate a fundamental part of Canada's constitutional structure—to the extent that, according to the Supreme Court, abolishing the Red Chamber requires unanimous approval of the provinces.

Unless someone can muster the necessary support to reform or abolish the Senate, it will not only retain the right but (arguably) the responsibility to closely scrutinize legislation passed by the House of Commons. The only question is how far it should go in doing so.

Between 2006 and 2015, when Harper’s Conservative Party was in power, the Senate was relatively reluctant to assert its presence. It amended only 14 bills passed by the House of Commons during that period — 11 government bills and three private member bills.

Justin Trudeau took office after he had already expelled Liberal Senators from the Liberal caucus. He embarked on fulfilling his pledge to appoint independent senators with relatively free rein to do as they pleased. Strictly speaking, only three senators have any connection with the current Liberal government: the government representative in the Senate, the legislative deputy to the government representative, and the government representative.

The result was a more active upper house. Over the past eight years, the Senate has amended 29 bills, including one introduced by a single member.

The emergence of a more assertive Senate — where most senators are not affiliated with major political parties — has inevitably raised questions about how or whether the Senate should impose limits on itself. Some critics envision an independent Senate becoming unruly and a major obstacle to legislation passed by the House of Commons.

A minimum amount of self-awareness might be enough to tell senators that, at some point, they risk inflaming public anger by frustrating the will of the House of Commons. Peter Harder, the first senator to hold the title of Government Representative, proposed some possible basic rules that the newly independent Senate might pay attention to in an article published in 2018.