Federal Conservatives called Wednesday for the Trudeau government to start talks with U.S. about joining its ballistic-missile shield, after their own party refused to do that during its decade in power.
The Tories explained their change of heart by pointing to North Korea's recent sabre-rattling as well as revelations last month that official U.S. policy is to not defend Canada from a ballistic missile attack.
"The last six months have been a gamechanger," Conservative foreign affairs critic Erin O'Toole said during a news conference outside the House of Commons.
"Accordingly, we're urging the government to fill the one gap that exists in North American defence."
North Korea has conducted several provocative nuclear and ballistic missile tests in recent months and some fear Canada could be caught in the middle of a conflict between that country and the U.S.
Those fears grew after Lt.-Gen. Pierre St-Amand, deputy commander of the North American Aerospace Defence Command, revealed the official U.S. position is not to stop a missile attack on Canada.
St-Amand, who appeared before a parliamentary committee last month, acknowledged U.S. officials could ultimately intervene, but such a decision was not guaranteed.
The U.S. actually invited Canada to join its continental missile-shield system more than a decade ago, but then-prime minister Paul Martin opted against it in 2005 following a divisive national debate.
Canada has since been on the sidelines as the U.S. has spent more than $100 billion building a series of land- and sea-based interceptors to stop the type of limited attack North Korea might launch.
One of the big questions facing any discussion with the U.S. about missile defence will be how much Canada should contribute to the controversial program, whose actual effectiveness has been questioned.
Conservative defence critic James Bezan would not say how much is too much for his party.
"Nobody knows what is going to be requested of Canada," Bezan said. "So it's up to the government ... to explore what opportunities exist for Canada to join the program."
Prime Minister Justin Trudeau seemed to close the door on joining ballistic missile defence in August, saying Canada would not change its position "any time soon," but re-opened it a crack last month.
"We have not changed our position at this point," Trudeau said on Sept. 19, "but we continue to engage in thoughtful ways to ensure we're doing everything we can and we must do to keep Canadians safe."
The Liberal defence policy, released in June, was also vague on missile defence, saying the threat was just one of many being discussed as Canada and the U.S. looked to modernize North America's defences.
The NDP has come out strongly against joining, saying missile defence will lead to another arms race by encouraging potential foes to build their arsenals to overwhelm any missile shield.
Former national security adviser Richard Fadden warned at a conference hosted by the Canadian Global Affairs Institute that it is only a matter of time before North Korea can attack North America.
"The discussion is academic whether they can do it today or tomorrow or next week, because they're going to be able to do it," Fadden, who advised both Harper and Justin Trudeau, told audience members.
"So what are we going to do about it in this country? And what's the United States going to do about it?"
Fadden said the defence policy's failure to address ballistic missiles was a "real gap," even as he lamented the lack of political discourse over the government plans to address the threat.
"The (prime minister) and ministers have gone out of their way since the policy became public not to talk about it except to say everything is on the table but nothing is on the table," Fadden told participants.
"We can do a whole variety of things. But not talking about it, it seems to me, is unhelpful."
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