The recent listeriosis outbreak - blamed for 20 deaths so far, making it the deadliest food-borne crisis ever in Canada - provided one of the first significant non-economic parries of the evening.And here's another:
Dion pointed to a Canadian Medical Association Journal editorial that denounced the Harper government's weakening of the food inspection system.
But Harper said the editorial was written by "a Liberal."
"Mr. Dion is talking about a Liberal who wrote that article. That is not the medical association's position. The association stated clearly that that was the case."
Both May and Dion said Harper's response was typical of the way he dismisses all critics.
"Whenever we contradict you, you accuse the others of being partisan. That's not leadership, Mr. Harper," said Dion.
At one point, when the line of questioning turned to issues of leadership, civility and decorum, Dion directly accused the prime minister of diminishing democracy.
"You've failed here, Mr. Harper," Dion said, citing the campaign controversy that erupted two weeks ago when a Tory operative dismissed the angry father of a slain Canadian soldier as a Liberal.
"You've had this problem throughout the election campaign. You can't continue like that. We have to have a leader with a sense of pluralism and respect."
Harper was left rather quietly agreeing with Dion that "we don't need personal attacks" in our political debates.