Justin Trudeau became a progressive hero when he announced in January that Canada would be accepting and welcoming refugees:

But it turns out offering to accept thousands of refugees isn’t so easy. The Guardian reports the immigration system in Canada is being overwhelmed:

Since the start of the year, more than 11,300 people have crossed into Canada by foot from the US. The pace has picked up in recent weeks, with as many as 250 people a day – many of them driven by fears of Donald Trump’s crackdown on immigrants – entering the country at remote, unguarded locations. Doing so allows them to skirt a longstanding pact that bars most refugee claimants in the US from applying for asylum in Canada.

As Canadians officials scramble to process and house the new arrivals – turning Montreal’s Olympic stadium into a temporary welcome centre, deploying the military to set up a 500-person camp at the border and setting up a temporary tent city in a small Ontario city – Trudeau has set out to tone down the welcoming image his government has cultivated since taking power.

“For someone to successfully seek asylum it’s not about economic migration,” Trudeau told reporters this week.

As you read over all of that don’t skip the part about the “longstanding pact” that bars refugees from applying for asylum in Canada. It turns out Canada has an agreement with the United States which says refugees must apply for asylum “in the first safe country they arrive in.” In other words, all of the people coming across the U.S. southern border aren’t eligible to claim refugee status in Canada because they entered the U.S. first.

Obviously, if you’re an immigrant traveling north who wants to respond to Trudeau’s #WelcomeToCanada message, you can’t show up at a U.S. border crossing because authorities would know you didn’t arrive in Canada first. And that means Canada can turn you away. Thanks to the first safe country rule, you’re America’s problem. However, if you suddenly show up in Canada not having crossed the border from the U.S. you can claim asylum in Canada. So thousands of people are slipping across the northern border away from the border crossings and checkpoints.

Canadian MP Jenny Kwan says, “If the prime minister was serious about reducing unsanctioned border crossings, let alone truly welcoming refugees, he would have already suspended the Safe Third Country Agreement.” But just this week Trudeau said he had no plans to do that.

So after making a big show of his open borders policy, it turns out Trudeau has created a mess and is now warning that people coming north illegally, or for a better job, or even asylum seekers who set foot in America first aren’t welcome after all.