"The Canada-EU free trade agreement is a big deal, it is a very big deal," Harper said with a smile, as former Conservative prime minister Brian Mulroney watched him from the main table of honour.
"I have said it is the biggest deal in our country's history, a claim I understand has been disputed in some circles," the prime minister said during a luncheon speech at the Board of Trade of Metropolitan Montreal on Friday.
Mulroney said in recent weeks the CETA deal was a big deal, but that it wasn't in the same league as the North American Free Trade Agreement he negotiated with the U.S. and Mexico in 1993.
NAFTA vs. CETA
Harper decided to tackle that question directly: "Which is the bigger deal: the original Canada-U.S. free trade deal, which of course led to NAFTA, or negotiations which we have just concluded with the European Union?"
The prime minister hailed the original deal as "an incredible victory" for Canada, even "revolutionary."
He recalled the fear-mongering that ensued after the deal was heavily criticized by anti-globalization groups whose scare tactics, Harper said, proved to be not only wrong but "totally false" even today.
"The Canada-U.S. free trade deal "has become one of the sturdiest foundations upon which the unprecedented strength of the Canadian economy today is based," the prime minister said.
Harper drew applause from the crowd when he said Canadians were indebted to Mulroney's Conservative government for paving the way for Canada's recent trade deals including the "historic" free trade agreement with the European Union.
"Now the case for why a free trade deal with Europe is the biggest," Harper said with a chuckle. His sense of humour was not lost on the business crowd who laughed along with him.
Harper said Europe's population, at 500 million people, is larger than that of the U.S., making it the largest integrated market in the world.
"The agreement with the European Union gives us as Canadians an opportunity, a unique opportunity we have long sought: the ability to lessen our dependence on the American market and to diversify our trade beyond the United States," Harper said.
Harper credited former Quebec premier Jean Charest and his chief negotiator, also a former Quebec premier, Pierre Marc Johnson, for their key role in the successful negotiations of the CETA deal.
The prime minister applauded "the broad Quebec consensus" then and now, adding that this time the consensus was also strong across the country.
Mulroney's deal 'one of the biggest'
After Harper's appearance, Mulroney was asked by reporters about the prime minister's comparison, particularly his reiteration that the EU deal is the biggest in Canadian history.
"I don't think he said that," Mulroney initially replied with a laugh, before commenting on the free-trade-deal debate: "Well, I'll let others judge that."
Mulroney, who has occasionally had a frosty relationship with Harper, said the prime minister did well with the European deal and he called it a very important achievement.
He then underscored some of the merits of his former government's Canada-U.S. deal.
Mulroney said the U.S. agreement set off an "explosion" of trade of up to $750 billion per year, making it "one of the biggest trade deals between two countries in the history of the world."
He also credited it with creating 4.5 million jobs in Canada, 80 per cent of which are directly linked to free trade.
"Not bad," Mulroney said.
"So, I hope the new treaty will do the same thing. It will be wonderful."
A longtime Conservative who once worked for Mulroney told CBC News there was a good vibe in the room.
Harper and Mulroney were seated at the same table, on opposite sides of each other, flanked by Montreal Mayor Denis Coderre, prominent Quebec business leaders, members of the Montreal board of trade and current federal ministers.
Harper was accompanied by International Trade Minister Ed Fast, the minister in charge of negotiating the CETA deal, and Denis Lebel, the minister of infrastructure, communities and intergovernmental affairs and minister of the economic development agency of Canada for the Quebec region.
Following his speech, Harper participated in a question and answer session led by Michel Leblanc, the president and chief executive officer of the Montreal board of trade.
Last month, Canada and the European Union reached a political agreement on a free trade deal the federal government said could boost Canada's annual income by as much as $12 billion annually, and bilateral trade by 20 per cent.
Harper travelled to Brussels to seal the agreement a day after Parliament returned with a throne speech that laid out the government's agenda.