U.S. President Donald Trump pledged on Monday to "handle" the evolving threat posed by North Korea's increasing ballistic missile capability.

What that means — for the world at large — is anyone's guess, and just how much blowback from that promise could strike Canada is a matter of broadening debate.

Prime Minister Justin Trudeau condemned as "provocative" and "irresponsible" the recent intercontinental ballistic missile test, but was largely silent on the ramifications for this country and the stark choices his government may face.

The launch, which took place Friday, reignited fears North American cities could be in Pyongyang's somewhat shaky crosshairs.

North Korea's leader Kim Jong-un claimed his country's missile now has the range to hit Chicago.

Most experts agree Canada would not be deliberately targeted by the increasingly belligerent regime, but the possibility a crude, off-course missile might inadvertently fall short somewhere north of the U.S. border is a real fear.

"Canada could be hit by a North Korean missile that was aimed at the continental United States," said Richard Weitz, of the Washington-based Hudson Institute.

The Liberal government chose in its recent defence policy to remain outside of the U.S. anti-ballistic missile program, upholding a decision made over a decade ago by Prime Minister Paul Martin. Opposition to involvement in those kinds of American plans stretches back to the 1980s and the Reagan Administration's so-called "Star Wars" plan.

But Weitz argues that North Korea's increasing capability means countries like Canada face a new world.

"Since the situation has changed, I would say I think the Canadian government should consider whether the current policy best supports its interests," said Weitz. "I think excluding the option given the changed situation is unwise."

Tories suggest a change in course

The recent defence policy says Canada "will engage the United States to look more broadly at emerging threats and perils to North America, across all domains as part of Norad modernization."

This picture taken on July 4 and released by North Korea's official Korean Central News Agency (KCNA) shows the successful test-fire of the intercontinental ballistic missile Hwasong-14 at an undisclosed location. (STR/AFP/Getty Images)

The policy describes that as a "prudent, holistic approach," but without more specifics, Weitz said it amounts to nothing more than the long-standing "de facto policy" of relying on the Americans to shoot down an incoming missile, or missiles, that may threaten Canada.

"A politician, of course, wouldn't want to say that because … it makes it look like the fate of the Canadian people and the defence of the Canadian people is outside their hands," he said. "I think Canadians would generally trust any administration in Washington to protect them, but it's still an uncomfortable stance."

The Opposition Conservative defence critic tweeted on Monday that his party's own defence policy consultations, held in tandem with the Liberal government, shows there's public support for a change in course.

The sentiment was echoed by the party's foreign affairs critic, MP and former cabinet minister Peter Kent, who cited the latest developments in Korea as "yet another reason [Canada] must join U.S. in ballistic missile defence."

The Conservatives are taking that position despite having spent a decade in power where no effort was made to reverse Canada's self-imposed exclusion.

In a recent interview, Peggy Mason, president of the Rideau Institute, a public policy think-tank, said there are real questions about whether the U.S. missile defence would actually work and what she describes as the program's enormous cost.

Canada's military commitment

Beyond the military and policy discussion related to missiles, there are questions about what sort of expectation there would be for Canada should the tense standoff on the Korean Peninsula escalate into war.

It is possible the United Nations could ask Canada to resume its military commitment, alongside the 16 other countries that fought the Korean War between 1950 and 1953.

If the shooting starts, the United States-South Korea Combined Forces Command would be in charge, but policy documents prepared for former defence minister Peter MacKay in 2010 say reinforcements could be assembled and sent under an existing, decades-old UN framework.

As one of the original troop-contributing nations, Canada would likely be among the first asked, although unlike NATO, there is no binding, clear-cut obligation for the country to join.

Diplomacy still an option

An expert on nuclear non-proliferation says he remains optimistic there will be no rogue missile strike, nor a resumption of fighting.

Despite Trump's heated rhetoric on Twitter and the recent U.S. show of force involving a flyover of the Korean Peninsula by two B-1 bombers, Douglas Roche said he believes Washington realizes a war would be catastrophic.

He said the Americans could attempt to completely destroy the North Korean military; opt for a limited strike to wreck the country's nuclear and ballistic missile capability; order a decapitation attack to take out Kim's regime — or try diplomacy.

"I'm not filled with optimism, but I do see a ray of hope," said Roche a former member of Parliament and senator and Canada's ambassador for disarmament to the United Nations.

South Korea's newly elected government wants to open a dialogue with the North, a policy departure from the previous administration.

The Trump White House has said it's not interested in talking, and the era of showing "strategic patience" as articulated by the Obama administration is at an end.

But Roche, who believes the only solution to the current impasse is a world-wide treaty banning nuclear weapons, said the U.S. may have no choice but to talk and strike some kind of deal to limit North Korea's nuclear program, as was done with Iran.

He also said the other side is not blind to the potential fallout.

"The leadership of North Korea is not blind to the realities of what would happen to them, if they themselves launch a strike," said Roche.