A senator can technically be fired – but it's likely up to colleagues to do it.
An appointment to Canada's Upper Chamber is not necessarily set in stone until retirement, though early departures aren't common. Senators can theoretically vote to disqualify a colleague under certain circumstances, said Ned Franks, a professor emeritus in the department of political studies at Queen's University.
"They just need a vote," he said. However, a senator would likely simply step down before any such vote occurred, he said. The rules are hardly well-defined.
"I know other people would argue the other way," said Prof. Frank, a long-time researcher and author on Canadian Parliament. "But as far as I'm concerned, the Senate is master of its own business."
The Senate has become a lightning rod amid controversies surrounding senators Mike Duffy, Pamela Wallin, Patrick Brazeau and Mac Harb. Under the Constitution, there are five categories under which a senator can be "disqualified," or kicked out.
Those include failing to show up for two consecutive sessions of Parliament, each of which typically last more than a year; declaring allegiance to, or becoming a citizen of, another country; becoming bankrupt or insolvent; committing treason, being convicted of a felony "or any infamous crime," or if the senator fails to live in the region he or she is to represent.
It's up to senators to police themselves – and previous complaints have been met with inaction.
Shortly after Ms. Wallin's announced appointment, University of Regina professor emeritus Howard Leeson began inquiring about her residency – whether she spent enough time in her home province.
"She and Duffy were appointed at the same time, and had the same problem," said Prof. Leeson, a constitutional scholar. After five years, he's received only brief statements from Senate officials, not saying how they determine residency, but only that Ms. Wallin is qualified and a resident of Saskatchewan. "I frankly don't believe that," Prof. Leeson said.
The issues have now been thrust into the spotlight. "It's such a perfect storm, in a sense, because normally, as you know, [the Senate] just sits there as a house of patronage," Prof. Leeson said.
The powers of the Senate, and method of appointing senators, could also be fundamentally changed by amending the Constitution, he added. That requires the support of the Senate, the House of Commons and at least seven provinces containing a majority of the Canadian population. It would be a monumental undertaking.
"Once you open that door, people want to do more than simply some small changes. They want to make large changes," Prof. Leeson said. "It's a recipe for inaction. People say, 'Oh, we can't act.' So they don't."
But the Senate still does valuable work, particularly in its committees, Prof. Franks said. "It's not a bad body. It's got bad press because it's got so many obvious vulnerabilities."