Although the Crown and defence agree he likely did not act alone, Sona, 26, was the only person charged in the so-called robocalls scandal, in which 6,700 calls were made on the morning of the 2011 federal election with misleading information on where to vote.
In August, Sona was found guilty of wilfully preventing or endeavouring to prevent an elector from voting, which carries a maximum penalty of five years in prison and a $5,000 fine.
"When courts are confronted with individuals who commit an offence of this nature, a large-scale attempt to defraud individuals of their constitutional right to vote, (18 to 20 months) is the fit and appropriate sentence," Crown attorney Croft Michaelson said in his submission to Justice Gary Hearn.
"(Jail time is needed) to deter this type of conduct in the future, so it doesn't ever happen again, and more importantly, so those involved in the electoral process are aware we have rules and the rules have to be followed.
"And if you interfere with the electoral process and you do something that's aimed at undermining the constitutional right of citizens to vote, the courts will deal with that."
Sona has also refused to accept responsibility for his role in the scheme, Michaelson added. "We have a complete lack of contrition. We have no remorse."
Lawyer Norm Boxall argued that Sona has already suffered enough, given the embarrassment and damage to his reputation the controversy has caused.
Sona has been working as an apprentice machinist of late, earning between $12 and $14 an hour, court heard.
"In my submission it's not necessary to separate Mr. Sona from society," Boxall said. "We're not at risk (from) him, he's not dangerous."
Boxall asked Hearn to consider a short suspended sentence or a six-to-12-month conditional sentence with house arrest, parole and a requirement to complete community service.
The message that the authorities won't tolerate election fraud has already been received and understood by everyone in Canadian politics, said Boxall, noting his client was just 22 in 2011 and had no prior criminal record.
If Hearn decides jail time is required, Boxall argued a "short, sharp sentence" would be sufficient.
"It may be that your honour feels that some form of real custody is required to denounce or deter, but in my submission, the length of it in one sense isn't very important in this type of case, the symbolism of it may be," he said.
"It doesn't have to be a long onerous sentence, it only needs to be a … symbolic sentence."
Boxall said Sona's involvement in the scheme was more of a misguided "prank, or an election trick, or game," rather than a grand conspiracy or "attack on democracy."
Jail time is called for, but if Sona is to receive a conditional sentence, it should be as harsh as possible — not something "that would simply require the accused to spend his evenings and weekends in his apartment where he can watch TV and Twitter away," Michaelson said.
Hearn asked Sona if he had anything to say before a sentencing decision was made. Sona shook his head no.
Sona is scheduled to receive his sentence on Nov. 19.
Earlier Friday, court heard from two of the 16 people who submitted victim-impact statements following the election.
Sarah Parro said she initially believed that the automated call she received on election day was legitimate, but was later convinced by her father that something about it was suspicious.
Parro said she felt naive assuming such fraud would never happen in Canada. The experience left her disillusioned with politics, she added.
"(It felt like) we are just pawns in a rigged chess game, no different than stolen elections in Third World countries."
Anne Budra, the returning officer responsible for the vote in Guelph, said her reputation and the credibility of Elections Canada were "threatened in a very serious manner" by the phoney calls.
"What happened was extremely serious for our democratic way of life in Canada, Budra said. "It was extremely stressful and disappointing and had very serious effects."
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