Outgoing Canadian Ambassador to the U.S. Gary Doer says security is going to be the biggest challenge for Canada and the United States in the years to come.

In a sit-down interview with CTV’s Power Play, Doer said the allies will have to continue to work together in the fight against terrorism at home and abroad.

“What is going to be the most challenging issue facing Canada and the United States in the next period of time, it’s going to be keeping the world safe and keeping our neighbourhoods safe.”

Doer recounted U.S. President Barack Obama’s immediate support following the Oct. 22, 2014 terror attacks in Ottawa. “We had … President Obama stand up and … offer his condolences to the Canadian people, to the Canadian military, and again speak to the relationship that we have not only as friends but as partners in keeping our neighbourhoods safe. And that’s crucial going forward.”

Doer, whose six-year stint in Washington wraps up next year, warned that there will always be ups and downs between Canada and the U.S. For instance, while the U.S. rejection of the Keystone XL pipeline was a setback for Prime Minister Justin Trudeau and Obama, Doer said the climate change talks in Paris marked a positive meeting for the two leaders.

“I expect Canada-U.S. relations to continue to move forward, but I also know that with $2 billion of trade a day, and sharing all the water and lakes we have, and the ecosystem we have, we will always have a bit of speedbump in our relationship,” said Doer.

“I don’t want to sugar coat anything. There’s going to be disagreements. We’re two sovereign countries.”

Those words of advice will be important for the next ambassador – an appointment Trudeau will have to make early in his mandate.

Devil’s Brigade recognition highlight of ambassadorial career

The envoy job comes with many perks and thrilling moments. But for Doer, his visits to the Oval Office and the Pentagon weren’t the highlights of his time in Washington. Rather, it was the awarding of the Congressional Gold Medal to the Devil’s Brigade, an elite Second World War commando unit.

“It took us four years to finally get approval of the Congressional Gold Medal,” said Doer. “And making the point that these people were 88, 89, 90 years old.”

The unit, comprised of Canadian and U.S. soldiers, were the precursors to today’s Special Forces, including Canada’s Special Operations Regiment and the U.S. Navy Seals. The men took on some of the most dangerous and difficult missions in the war, never losing a single one of the 22 battles they fought. CTV’s W5 profiled the Devil’s Brigade earlier this year.

U.S. election will be “fought in the middle”

Doer acknowledged Donald Trump’s lead in the Republican presidential pack, but said it’s too early to predict the 2016 election outcome. He said that candidates appeal to the “extremes” in their parties during the primaries stage of the election, but that the vote is fought and won in the “middle.”

“The American public in places like Florida, Pennsylvania, Ohio, Colorado, New Mexico, Virginia, North Carolina, they’re kind of middle voters and they will determine, under the electoral voting system, who the president is. And they always get it right.”