Former defence minister Peter MacKay says he laments not signing on to the U.S. ballistic missile defence program when he had the chance.
The policy was a matter of intense debate for the former Conservative government, as it was for the previous Liberal administration.
What has changed lately, says MacKay, is the threat from North Korea, which over the last month has demonstrated an increasingly sophisticated capability for launching intercontinental ballistic missiles.
There have been two successful flights of missiles that could potentially reach North America.
"We share a great deal of intelligence with the United States and if they're alarmed, we should be alarmed," MacKay told CBC News. Not being involved in the program is "a huge problem," he added.
Coming into office in 2006, the Conservatives had said they were in favour of joining the George W. Bush Administration's missile defence shield. But throughout almost a decade they made no attempt to buy into the program, which was the subject of furious debate under Paul Martin's Liberals.
"There's no denying we did not move in that direction, although, there were discussions, and I personally, as [former] defence minister, have regrets we weren't able to advance those discussions," he said.
Both MacKay and former Liberal defence minister Dave Pratt spoke in favour of joining the missile defence program when they testified before a Senate committee a few years ago.
The Senate defence committee has twice recommended joining, but in June Prime Minister Justin Trudeau's government opted not to lift the prohibition on involvement — even though Canada is paying for, and participating in, a similar NATO missile shield intended to protect Europe.
Pratt said that's an important point and — in light of the recent tests by Pyongyang — the decision needs to be revisited in Parliament.
"I think it's time to have this debate front and center for Canadians for the sake of safety and security of North America," he said.
MacKay said he believes very few people in the general public "grasp the gravity" of the current situation and the technological advances that have been made by the regime of North Korean leader Kim Jong-un.
"Given the tone, the tenor of this threat, I really think it's time for Canada to move past this … allergic reaction that, I think for years, has existed to Canada entering into ballistic missile defence program with the United States."
But there are some who are growing increasingly skeptical, and in some cases dismissing outright, the rising tide of rhetoric.
"The idea that North Korea poses a threat to either the United States or Canada is really, really farcical," said Peggy Mason, president of the foreign policy think-tank, the Rideau Institute.
She said fear of U.S. military action, particularly since 9/11, is what's driving the development of the reclusive regime's missile and nuclear programs, which have been condemned repeatedly by the United Nations.
South Korea's new government has expressed a willingness to open a dialogue with the North, and Mason says they should be encouraged to do so, particularly by Canada.
"Start with military-to-military confidence building dialogue between South and North Korea. I think we should start with that," said Mason.
"We should get tensions ratcheted down and not give North.Korea any reason to continue in its bellicose manner."
There is no military solution to the crisis, she added.