OTTAWA — The decision on whether or not Stephen Harper testifies at Sen. Mike Duffy's fraud, breach of trust, and bribery trial could ultimately rest with NDP Leader Thomas Mulcair or Liberal Leader Justin Trudeau.
But first, he would need to be subpoenaed and called to testify, and Mulcair or Trudeau would need to win the election.
So far, there has been no suggestion by the Crown or Duffy's lawyer, Donald Bayne, that the Conservative leader is on any new list of potential witnesses.
Conservative party spokesman Stephen Lecce refused to say whether Harper would invoke parliamentary privilege if he were called. "As the RCMP said nearly two years ago, the PM has no knowledge of this matter," Lecce responded in an email to the hypothetical question.
But if Harper were called, and the NDP or the Liberals won on Oct. 19, his ability to invoke parliamentary privilege to avoid testifying would rest with his former political foes.
Parliamentary privilege refers to the list of immunities from the law that are centuries old and provided to members of Parliament, individually and collectively, to allow them to do their legislative work unfettered.
According to parliamentary experts Terry Moore and James Robertson, the most important privilege is the freedom of speech in Parliament (MPs can't be sued for defamation if they say something inside the chamber — outside the chamber that right doesn't apply). Historically, MPs have also been protected from arrest in civil matters, although that is no longer the case. MPs are also exempted from jury duty, and members and senators are exempt from attending court as witnesses.
"That does not mean that parliamentarians do not appear in court. They may do it voluntarily if their testimony is absolutely required," Moore and Robertson note.
Parliamentary privilege extends to 40 days after Parliament is dissolved — in this case, when the election was called — to 40 days before the beginning of the next Parliament.
And it is the prime minister who controls the parliamentary calendar.
The current portion of Duffy's trial is scheduled to last until Aug. 28. It resumes again on Nov. 18, remaining in session until Dec. 18.
So, if Harper wants to claim privilege — as he did in 2007 to avoid a giving a deposition in a defamation lawsuit — he has to hope that either Mulcair or Trudeau calls Parliament back to work in November or December.
If they call Parliament back to work in January, he might be forced to testify.
Related from Duffy's trial:
Also on HuffPost