Prime Minister Justin Trudeau sent a message that Canada will not be browbeaten when he reasserted his position Aug. 23 that the country will act in its own best interests on the issues of troops for Afghanistan and continental missile defence.

U.S. President Donald Trump announced last week that he would boost troop levels and extend American involvement in the ongoing struggle against Taliban and ISIS in Afghanistan, though he offered no specifics. “We will ask our NATO allies and global partners to support our new strategy, with additional troop and funding increases in line with our own,” Trump said. “We are confident they will.”

Not Canada, however. Trudeau reiterated his assertion, made earlier this spring, that the government has no plans to revive Canada’s mission in Afghanistan.

As for ballistic missile defence, Canada opted out in 2005 after a divisive national debate. While individual MPs, including some Liberals, want the issue reopened, the government has declined to change policy.

“On those cases, we will always take the decisions in terms of what is the best interests of Canadians,” Trudeau said. “And our long-standing positions on those two issues are not going to be changed any time soon.”

Canada ended its combat mission in Afghanistan in 2011, and in 2014 it withdrew the last of its advisers who were helping train Afghan army and police. It ended a 13-year commitment that cost 162 Canadian lives and billions of dollars.

Trudeau indicated in May that Canada would not be going back.

Ballistic missile defence, meanwhile, has surged back into the national consciousness as tensions between Trump’s administration and North Korean leader Kim Jong-un have escalated.

Kim’s repeated provocations, backed by increasingly threatening missile tests and evidence suggesting the country has or is about to have a nuclear-armed missile capable of reaching North America, reached a boiling point recently when Trump warned of “fire and fury” if North Korea continued flaunting its nuclear weapons program.

Ottawa’s recent defence policy review makes no direct mention of ballistic missile defence. Its section on continental defence promises to improve aerospace, maritime defence and satellite capabilities, and to procure advanced fighters. Its silence on missile defence was seen as endorsement of existing policy.

Defence Minister Harjit Sajjan’s office told the Hamilton Spectator last week that ballistic missiles are only one threat under consideration as Canada and the U.S. look to modernize North America’s aging early-warning air defence system.

“The government of Canada has already committed to examining, through Norad modernization, territorial defence against all perils,” said Sajjan’s spokeswoman Jordan Owens, including “threats from cruise missiles, ballistic missiles and other future technologies to provide Canadians with greater security at home.”

The two-decade-old U.S. ballistic missile defense policy, for which Congress approved $190 billion between 1985 and 2017, aims to protect the U.S. against limited long-range missile strikes from states such as Iran and North Korea.

It doesn’t address potential threats from Russia and China “due to the significant technical, financial and geopolitical challenges,” according to the U.S.-based Arms Control Association, a non-partisan group promoting effective arms-control policies.

“The technical capabilities of the system, the scope of the ballistic missile threat, the deterrence and assurances…the cost-effectiveness of shooting down relatively inexpensive offensive missiles with expensive defensive ones, and the impact on strategic stability of U.S. defenses with Russia and China,” have all been matters of debate, the group said in a report updated in June.

The U.S. Department of Defense says existing U.S. missile defences have “demonstrated capability” to defend against a small number of simple, intercontinental ballistic missile threats that employ “simple countermeasures.”

A formal review of U.S. missile defence is taking what the association describes as a wide-ranging look at missile-defence policy and strategy. Its work is to be completed by the year’s end.

At a special meeting of the House of Commons defence committee in Ottawa last week, only the New Democrats came out against the unproven technology, calling for greater diplomatic efforts instead.

CBC reported that neither the Liberals nor Conservatives arrived with clear positions, with the latter deferring the issue to its upcoming policy convention.

Not that a clear position would have made much difference. Past endorsements of missile defence by the all-party committee and its Senate counterpart have been ignored.

What the committee did agree on is a parliamentary discussion on the issue of North Korea, which will inevitably include the subject of missile defence.