Senators are supposed to "be resident" in the province from which they are appointed. Duffy has lived in Ottawa since the 1970s, but was appointed to represent Prince Edward Island.
A P.E.I. professor raised concerns about Duffy's eligibility almost as soon as Prime Minister Stephen Harper announced on Dec. 22, 2008, that he would name the longtime broadcaster to the Senate.
Constitutional law expert David Bulger started questioning whether Duffy was, in fact, eligible for his seat two days after the announcement.
"What it comes down to is — does he have to be a resident in the province at the time when he's appointed? Some of us, and I am one of them, would argue yes," Bulger told the Guardian, a P.E.I. newspaper, in a story published Dec. 24, 2008.
The concern seems to have struck a chord: Duffy's diary notes he had a meeting in the office of then Senate government leader Marjory LeBreton a few weeks later.
Discussed with PMO
"Meeting Mike & Pam/Sen. LeBreton's office re: Prof. Bulger," he recorded on Jan. 6, 2009.
Senator Pamela Wallin was named to the Senate at the same time and, as a national broadcaster and then a diplomat, had also been living outside of her home province of Saskatchewan.
Bulger says the problem could have been avoided had Duffy moved to the Island before he was appointed to the Senate.
"The Constitution says that the person must be resident in the province," he told Rosemary Barton in an interview on CBC News Network's Power & Politics, emphasizing the word "be."
"That's the state at the time the Governor General issues his or her summons [to a senator]."
The same day as the meeting about Bulger's concerns, Duffy noted he met or spoke with Harper's then director of communications to get approval for scripted responses to questions about his residency.
"Check media lines with Kory Teneycke re: Pam&Mike," he wrote in the calendar.
Three days later, a staffer from LeBreton's office sent a memo that said the Senate is "master of its own house" and can define what residency means.
But that memo is a political document, not a legal opinion, according to the former law clerk of the Senate who testified this week.
'Property documentation' meetings
The now suspended senator's diary, containing notes of whom he met and what was discussed, was made public this week as evidence in Duffy's trial on 31 charges of fraud, breach of trust and bribery.
Duffy pleaded not guilty to all counts and says he didn't break any rules.
Even before the meeting in LeBreton's office, Duffy seems to have discussed his eligibility with then Senate clerk Paul Bélisle and an official from the Prime Minister's Office, according to the calendar.
On Jan. 2, 2009, Duffy noted a conversation with Bélisle and Dave Penner about property documentation. Penner was the PMO official in charge of appointments for 4½ years, including at the time Duffy was appointed. That was likely a phone call, as Duffy was in Charlottetown at the time.
On Jan. 5, Duffy met again with Bélisle "re property declaration."
One of the things Duffy did on the trip to Charlottetown was apply for a driver's licence, according to the calendar.
On Aug. 11, 2009, he picked up P.E.I. plates for his car.
Duffy started claiming per diems and a housing allowance for his Ottawa property on Dec. 23, 2008. Senators are entitled to claim a living allowance for their secondary residence in the National Capital Region — defined as within 100 kilometres from Parliament Hill — if their primary residence is outside those boundaries.
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