Here are some highlights from the day:
Witness No. 1
The Crown called its first witness: former Senate law clerk Mark Audcent, who retired from the upper chamber in 2014 after serving there for more than 30 years.
Audcent was responsible for drafting the "Senate administrative rules," which deal with the business of running the Senate, including the expenses of senators. His testimony largely focused on those rules and others governing the appointment of senators, chief among them how a senator's "residence" gets defined.
In Audcent's view, residency is a matter of fact. "You have to be resident in the place, and that's the underlying requirement," he said.
But he acknowledged that there was no clear definition of "residence" in the context of either the constitutional eligibility of senators or the rules governing their expense claims.
What senators do in their spare time
When Audcent was asked how he defined residency, he set out a number of indicators, including where a person physically lives, where they get their government services like health care and where they socialize.
"Where you do business, where you bank, where you go to church, where your bowling league is, where you singing club is, all those social connections that add up to a package saying this person is resident here," he said.
"Is bowling a big pursuit amongst members of the Senate?" asked deputy Crown prosecutor Mark Holmes to much laughter from the courtroom. Audcent didn't answer.
What the documents say
It was Dec. 22, 2008, when Prime Minister Stephen Harper announced Mike Duffy would be appointed to the Senate.
Audcent testified that the very next day, Dec. 23, Duffy received the standard orientation briefing for new senators — an hour-long presentation from senior Senate staff about the rules and business of becoming a senator.
Duffy got the briefing before he was actually a senator, Audcent said — the official date of his appointment was Jan. 2, 2009.
That's not all he got: his expenses were covered as well.
Documents entered as evidence at the trial show Duffy claimed the per diem expense available to senators away from their provincial residence on Dec. 23, 28 and 29, getting $81.55 for each day.
Between Dec. 29, 2008 and Jan. 4, 2009, he also billed the Senate for more than $4,300 so he and his wife could travel to Charlottetown.
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