Former prime minister Brian Mulroney lavished praise on former U.S. president George Bush senior Tuesday, saying he was a "fantastic" guy whose example offered a sharp contrast to that of the current tenant of the White House.

"George Bush was fantastic and still is," Mulroney told an audience in Ottawa. "I tell you, if you want to see a contrast between a civilized, modest, thoughtful, generous leadership and what you're seeing today, there you go."

Mulroney made the comments during a question and answer session with a general audience at the Library and Archives in Ottawa, before taking questions from reporters.

Mulroney was prime minister when both the original Canada-U.S. Free Trade Agreement and the North American Free Trade Agreement were negotiated. He said U.S. President Donald Trump has made dealing with the U.S. a challenge for the government of Prime Minister Justin Trudeau.

"I got a bonus with those guys that you saw there, Reagan, Bush and Clinton," Mulroney said. "These were [a] little different from what's going on now and so I had it easier than Justin does.

"Now we have President Trump, who is, how shall I say, unorthodox in some of his approaches. But he was elected by the people of the United States of America and I learned a long time ago that even if I disagree with an individual, if he was elected by the people, you have to deal with him and you only deal with people in respect. Otherwise you don't achieve anything."

Former Prime Minister Brian Mulroney spoke in Ottawa on Tuesday 1:54

Mulroney said he thought that Trudeau was doing a good job of putting aside his personal views about what he sees happening in Washington in order to get a NAFTA deal both Canada and the U.S. can live with.

"This is not an easy business, as you can imagine, certainly in recent years, but I think the government of Canada is handling this very complex file well."

Putting partisanship aside

Mulroney, who served as prime minister from 1984 to 1993, has been advising Justin Trudeau's government since Trump's election.

"I continue to work with him. As I said publicly, there is no Conservative way or Liberal way to negotiate a free trade agreement with the United States of America. There's only a Canadian way and so, if they think that I can be of assistance, I am happy to do it."

Mulroney also praised Trudeau for enlisting the help of former Conservative federal politicians Rona Ambrose and James Moore to present a united front on NAFTA, saying the former Harper cabinet ministers should be praised for putting their own political affiliations aside for the greater good of the country.

Mulroney employed the tactic himself when he was prime minister. He hired Simon Reisman, a Liberal who had negotiated the Canada-U.S. auto pact for former Canadian prime minister Lester Pearson, to negotiate free trade with the U.S.

"I think there are times when it's important that we set aside politics and come together as colleagues who can help the country a little bit and that's what I'm pleased to do," he said. "I have been working with Mr Trudeau for, certainly, a couple of years on this, and [Foreign Affairs Minister Chrystia Freeland], who is doing an excellent job by the way."

Giving Trump a win

Mulroney said Trudeau is not the only one facing challenges in trying to renegotiate NAFTA. U.S. Trade Representative Robert Lighthizer, he said, is facing his own challenges.

"There's no doubt that Bob Lighthizer is dealing with a special situation down there and the American side are on a pretty short leash because of President Trump's arguments," Mulroney said.

Specifically, Mulroney suggested Lighthizer has been somewhat confined to getting Canada to compromise on supply management in the dairy sector so that Trump can deliver the win he promised to Wisconsin farmers.

"You have to be foolish not to understand that there's not going to be a deal, period, unless there's a compromise in that area, because that's what [Trump] campaigned on and it's stuck to him, he stuck with it," he said. "So if we do not find a way to accommodate some of that, then we are not going to have a deal."

'I've never seen language like this'

This isn't the first time Mulroney has been critical of the Trump administration. In the fallout from Canada's G7 summit in June, a clearly upset Trump took to Twitter to call Trudeau "dishonest" and "weak" after the prime minister said he would not be bullied by the U.S. in NAFTA talks.

That message was quickly picked up by the president's senior officials, who echoed Trump's attack on Trudeau.

"There's a special place in hell for any foreign leader that engages in bad faith diplomacy with President Donald J. Trump and then tries to stab him in the back on the way out the door," trade adviser Peter Navarro told Fox News after Trump's Twitter attack.

When asked about the comments at the time, Mulroney said he was not impressed.

"I've never seen language like this. Least of all from subordinates of the president directed at the prime minister of their greatest friend and ally," he said. "This, I've never seen before. Nor has anybody else."