Former Prime Minister Stephen Harper and Conservative senators may have difficulty invoking parliament privilege should they be called to testify at Senator Mike Duffy’s trial, say some of Canada’s top experts in parliamentary procedure.

Harper, who named Duffy to the Senate, stepped down as Conservative Party leader but remains an MP, prompting some to speculate that he is staying on as an MP to avoid having to testify in the Duffy trial.

Harper has used privilege once before – to get out of having to testify in a civil lawsuit filed by Alan Riddell. Riddell had sought a Conservative Party candidacy only to be told the party wanted to run former whistleblower Allan Cutler.

However, experts like former House of Commons law clerk Rob Walsh say they’re not sure the same degree of privilege exists to get out of testifying in a criminal trial.

“The law of parliamentary privilege is unclear as to the extent to which it applies in respect of criminal court proceedings,” Walsh said in an interview with iPolitics.

“Clearly, a member of Parliament is not privileged against appearing where the member of Parliament is charged with a criminal offence but it is an open question in my mind whether the exemption of members from being compelled to testify in court applies or does not apply in respect of a criminal trial.”

The courts may not accept MPs privilege when it comes to criminal cases, he added.

“I’m inclined to think the courts would be loath to allow privilege to prevent a member of Parliament being available as a witness in a criminal matter. I’m inclined to think the courts would not want to grant and recognize an exemption to members of Parliament with respect of criminal proceedings but I’m just not sure.”

Harper could also have difficulty getting the House of Commons to back him up if the court insisted he testify, Walsh added.

“In this particular case, it would be a pretty cold day in July before a Liberal dominated House insisted on the privilege for the purpose of preventing Mr. Harper from testifying in the Duffy case. It just wouldn’t happen, I would think.”

Duffy’s high profile trial on charges of bribery, fraud and breach of trust resumes November 18. When Duffy was first charged, his lawyer, Donald Bayne, did not rule out calling Harper to the stand. However, the subject has not come up during the trial and Bayne has not returned phone calls from iPolitics.

There have also been indications some Conservative senators could be called by one side or the other to testify.

A half-dozen Conservative MPs appeared as witnesses in the spring to testify about partisan fundraising events Duffy appeared at in their ridings. Although the House of Commons was sitting, they did not invoke parliamentary privilege to avoid taking the stand.

The rule that allows MPs to invoke privilege to avoid testifying goes back to at least the 18th century. It stems from the principle that Parliament has the right “to the attendance and service of its members” and has priority over other claims on an MPs time.

Traditionally that has been interpreted to mean an MP can’t be called to testify until more than 40 calendar days after a session of Parliament or 40 days before the next one. However, that time frame was successfully challenged in British Columbia in 2003 in a case involving Liberal Paul Martin in which the court found that privilege should only apply while Parliament is in session.

Harper’s decision to call a 78-day election campaign means that it is now well past the 40 days after the last session. Prime Minister Justin Trudeau has announced the next session of Parliament will begin Dec. 3 – 15 days after the trial resumes.

Marjory LeBreton, former government leader in the Senate whose name has been raised several times during the course of the trial, retired on her 75th birthday during the summer and is no longer covered by parliamentary privilege.

Walsh isn’t the only expert who believes there is likely a distinction between civil and criminal cases when it comes to the privilege of MPs.

“In a civil suit, the House has recently, in modern times claimed that privilege and supported an MP’s claim,” said one Canadian expert in Parliamentary procedure who spoke on condition they not be named. “But when it comes to criminal matters, the House would probably be very, very careful – depending also on the context.”

“If you’re a material witness in a serious criminal court offence I think the House would just say no, the MP would have to attend,” he added. “If it’s just political grandstanding – let’s say somebody wanted to call (former) Prime Minister Harper to the Duffy trial without anything demonstrated to the judge that there is a material matter that testimony could affect the future of the accused – the House might say no, that’s a matter of privilege but I doubt it in the modern times.”

Ned Franks, a constitutional expert and professor emeritus at Queen’s University, said the privilege goes back “many, many, many centuries” and is designed to ensure the ability of MPs and senators to do their jobs is not obstructed.

“It’s not that they are immune from prosecution – it’s just restricted – and I’m not satisfied that the laws are clear enough and the precedent clear enough that you can give an absolute answer.”

Parliamentary Privilege in Canada author and former law clerk of the House of Commons Joseph Maingot says MPs may choose to testify if they feel their testimony could affect a criminal trial.

“In Canada, a Member of the House of Commons who has received a subpoena to appear in civil or criminal court while the House is in session may wish to attend where he feels his absence might affect the course of justice,” he wrote.

Reached by iPolitics, Maingot said he believes MPs’ privilege exempting them from testifying applies to both civil and criminal cases.

[email protected]