06/02/2015 04:00 EDT | Updated 06/01/2016 05:59 EDT

Duffy dispatched by party to help with candidate before 2011 election

OTTAWA - The trial of Sen. Mike Duffy isn't about electoral laws or riding financing, but some of the witnesses offer a glimpse at how party support is built and money spent before a campaign even begins.

On Tuesday, the court heard how Duffy was dispatched by the Conservative party to a fundraiser in a Vancouver Island riding in December 2010 — in the run-up to the 2011 election.

The Conservative candidate, Troy DeSouza, explained that he had organized a holiday event to support Cockrell House, an organization that helps homeless veterans.

DeSouza testified by teleconference that he issued an invitation to 40,000 people in the riding for the December fundraiser. Although it was ostensibly a non-partisan event, he contacted the Conservative party to ask if they could provide a speaker and was thrilled to learn it would be Duffy.

"In our view he was provided to us because of the hard work done by the local team on the ground," DeSouza said.

On DeSouza's Facebook page the non-partisan approach isn't obvious. Instead it reads, "Senator Mike Duffy shows his support for Troy DeSouza at the Esquimalt-Juan de Fuca Conservative Association’s Christmas Party."

At the time, Liberal MP Keith Martin was the incumbent, generally the type of person who would have organized such a community get-together.

"There was a lot of that going on, candidates were running around portraying themselves as the shadow MP, the MP-in-waiting, under the presumption that candidate would become the MP," Martin, now the executive director of a Washingon-based organization which promotes, global health issues, said in an interview.

Pre-writ campaign spending continues to be an issue of interest to Elections Canada. Parties can spend millions on advertising in that period, but it does not count toward their spending limits. Some candidates, meanwhile, are careful not to rent a campaign headquarters too soon, lest Elections Canada make them include the cost in their totals.

"You'd be campaigning as soon as you receive the official nomination from your party that you're the nominated candidate of record to run," DeSouza testified.

Duffy's trip to Vancouver Island was raised in court for a different reason. It figures among the charges related to travel expenses he incurred while travelling to allegedly personal or partisan events at Senate expense.

He has pleaded not guilty to 31 charges of fraud, breach of trust and bribery in connection to his Senate office, living and travel claims.

After the Cockrell House event, Duffy visited his daughter who was about to give birth in Vancouver — the real reason he flew across the country, the Crown has suggested.

Duffy's lawyer Donald Bayne emphasize two things when it comes to Duffy's travels — the Senate rules didn't prohibit trips to partisan events and during his travels he actually engaged in public business.

"He appeared in his senatorial capacity?" Bayne asked DeSouza.

"He did," DeSouza replied.

"This wasn't a private personal event for the Duffy family?" Bayne continued.

Said DeSouza: "You could never get a more public event than this. To this date, I'd be surprised if any campaign or organization would invite the entire riding to an event."