On Wednesday morning, with less than two weeks remaining in the federal campaign, Andrew Scheer worried aloud about MS-13, the notorious Salvadoran-American criminal gang.

The Conservative leader stood near Roxham Road in southern Quebec, where asylum seekers crossing from the United States have forced the federal government to establish an unofficial border crossing. As Scheer spoke, opinion polls and seat projections showed his party trailing the Liberal Party nationally and losing ground to the Bloc Quebecois in Quebec.

It was against that backdrop that Scheer turned his attention to "illegal border crossers" and the immigration system — and the fear that violent gang members might be entering the country.

The timing may be coincidental. But it's a particularly interesting moment for Scheer to grasp at fears about who might be getting into Canada.

These aren't worries that should be raised lightly. And Scheer's proposed solution raises a number of questions.

Scheer's primary concern regarding immigration is premised, in large part, on the idea that Canadians have lost confidence in the country's immigration system — the purported result of the thousands of people from other countries who have come to Canada from the United States in the wake of Donald Trump's election in 2016 and a series of subsequent changes to American immigration rules.

Close 'loophole'

Scheer's contention isn't clearly borne out by the available data on public opinion. Regardless, the Conservatives propose to close the "loophole" in the Safe Third Country Agreement that governs asylum claims in the two countries.

Under that agreement, asylum seekers are obliged to make their claims in whichever of the two countries they arrive in first. The basis for that rule is the assumption that the two countries have broadly similar immigration systems, based on the rule of law. The goal is to prevent so-called "asylum shopping," where an individual makes simultaneous claims in more than one country.

Conservative leader Andrew Scheer makes a morning announcement at the Canada-U.S. border on Roxham Road during a campaign stop in Lacolle, Que., on Wednesday. (Jonathan Hayward/The Canadian Press)

The wrinkle is that the agreement can only be applied at official border crossings. If an asylum seeker can get across the border at another point, Canada is obliged by international law to give them a fair hearing.

The use of the word "illegal" to describe those who cross the border outside of official border crossings is a subject of significant debate.

That aspect of Canada's human rights obligations led to the RCMP intercepting 20,593 people crossing the southern border at places like Roxham Road in 2017 and another 19,419 people in 2018.

Influx has declined

Many of those crossing into Canada outside of official border points may have legitimate claims. But as the issue heated up in 2017, the Trudeau government made a series of efforts to discourage irregular arrivals. The influx has not ceased, but the rate has declined. Though August of this year, the RCMP had intercepted 10,343 asylum seekers, 4,000 fewer than over the first eight months of 2018.

Scheer's proposal is to renegotiate the Canada-U.S. agreement so that it can be applied to the entire border. But renegotiation necessarily depends on the willingness of the other party to talk — and it's hard to know whether the Trump administration has any interest in being that co-operative.

There's also the optics problem of negotiating border security with a U.S. president whose immigration policies have offended observers around the world.

Even if asylum seekers could be turned away at any point along the border with the United States, Canada would still face the challenge of patrolling that length of territory.

The 'unofficial' border crossing at Roxham Road, seen here in August 2019, now has a permanent building staffed by RCMP officers, but a gravelly path is still all that separates the U.S. from Canada. This Pakistan family arrived on the overnight bus from New York. (Sylvia Thomson/CBC)

Asylum seekers could end up travelling to more remote (and dangerous) points of entry — asylum seekers entering Manitoba during the winter have suffered severe frostbite. The area at Roxham Road is an obvious target for those who want to cross. It's also a relatively easy border point for police to monitor.

Dealing with the border itself is just part of the answer, though. If people are coming to Canada or the United States because of problems in their native countries, nations like Canada and United States should be motivated to deal with those problems. But Scheer is also promising a 25 per cent cut to foreign aid, even if he insists that the remaining funds will be focused on the poorest nations.

The arrival of 50,000 people in the space of three years does not, in and of itself, amount to something that could be described as a "crisis." Nearly a million refugees came to Germany in 2015 as a result of the violence in Syria and Iraq.

But on Wednesday, Scheer mentioned a specific threat — MS-13, the gang that American politicians have invoked as a pressing danger, particularly as it relates to immigration.

The idea that members of the gang might be in Canada isn't new (it was raised as far back as 2008) but Scheer had hardly emphasized the threat as a reason to worry about the border — before Wednesday. When Scheer delivered a "vision" speech about immigration in May, he said nothing about the possibility that MS-13 members were slipping across the border.

Granted, Scheer's rhetorical approach to the migration debate has not always hit a consistent series of notes. In that same speech, he neglected to mention his opposition to the UN's Global Compact on Migration, a non-binding statement of principles that became a point of conflict after various far-right parties in Europe moved to condemn it.

Scheer was mocked for his comments about the compact after he came out against it in December 2018. He subsequently stopped talking about it.

Would withdraw from compact

But a Conservative spokesperson told CBC News that Scheer still opposes the compact and would withdraw Canada from it if he became prime minister.

The Conservatives often blanch when the Liberals condemn their rhetoric on immigration as extreme.

"I think we can all agree that we should be able to have an immigration debate in this country without the government calling the people who criticize their failures racists and bigots," Scheer said in May.

But his own half-step back from condemning the global compact suggests he understands how such politics can reflect poorly on the politician pushing it.