There is no good reason why anybody should be walking across unguarded sections of the U.S.-Canada border. The fact that scores of asylum seekers have made the dangerous walk from North Dakota into Manitoba or from New York and Vermont into Quebec is not a signal of Canada's welcoming generosity. Nor is it a security risk to Canadians.

But it is a danger – both a physical one to the migrants themselves (two have already lost fingers in minus 30 C weather, which could easily kill) and a larger danger to the integrity, successful functioning and public support of Canada's refugee and immigration systems.

An increase in numbers could overwhelm our resources, cause tragic deaths and undermine support for the refugee system. If Prime Minister Justin Trudeau and his cabinet want to keep that system sustainable and popular, they could end this crisis by doing three things:

Story continues below advertisement

Stop illegal entries by creating a legal path. People aren't making these crossings because they're an easy way into Canada. In fact, illegal foot crossings are an exceptionally difficult and expensive way into Canada: Some migrants have paid drivers enough to buy business-class airfare.

People make them because they're the only way into Canada. Under the 2004 Canada-U.S. Safe Third Country Agreement, Canada does not allow foreign refugee claimants who landed in the United States through its official border crossings: You're required to apply for asylum in the first country in which you arrive. But if they can get themselves physically onto Canadian soil, they will be arrested, detained, released and given an assessment, a hearing and a right to appeal.

This is not, as some have said, a flaw in the act; rather, it is a feature of the Canadian Constitution: Once in Canada, you are entitled to the full suite of rights – including due process and a fair hearing.

We can deal with this in two ways. One, as suggested by some MPs, would be to secure the border more, by adding hundreds or thousands more police and border agents. They would probably spend their days and nights processing a rising tide of border-crossers, at great expense.

The other would be to stop the illegal flow completely by creating a legal entry method, with processing centres at border crossings. The numbers would increase somewhat, but it would be far less expensive and much less dangerous – and it would look secure, fair and rational to Canadians.

Consider suspending the Safe Third Country Agreement. The treaty made sense when it was signed, because the United States and Canada both treated refugee claims similarly, and offered similar treatment to people pursuing those claims. (The worry then was that claimants would try to sneak from Canada into the United States.) That has changed under the Trump administration. Refugee claimants fear, first, that their claims will get a less generous hearing under the refugee crackdown, and second, that they might be held in awful detention centres while awaiting a decision.

Since the agreement no longer serves its intended purpose, it mainly creates perverse incentives. Illegal foot crossings are one. Another is an exemption provided in the treaty to "unaccompanied minors" – which might tempt someone to send a child alone across the border. Suspending the treaty wouldn't overwhelm us with migrants: There's a very limited supply of asylum seekers who've made it into the United States. And under current conditions, it is easier for them to fly directly to Canada.

Story continues below advertisement

Get people processed fast. Many of those border-crossers – perhaps most – won't qualify as refugees. They'll wait months for a hearing, then years for an appeal, before they go home or are deported (by which time they'll have roots in Canada, creating a second set of crises). Those who are legitimate refugees will also wait, in ambiguous status, in border towns for long periods and possibly in large numbers.

To avoid this becoming an enduring, high-visibility crisis with grave political implications, Ottawa should bring on board extra Immigration and Refugee Board staff and judges to work the border stations, so hearings can be made in weeks rather than months and appeals in months rather than years. This would cost, but not as much as supporting thousands of ambiguous people for years, or rebuilding the reputation of our immigration system. By making it legal, rational and quick, we can make the border act like a border again.