Here’s what the State Department recommends to U.S. travelers to Guatemala: Do not walk or drive at night. Request security escorts. In the capital, Guatemala City, do not hail taxis on the streets, and avoid 10 specific neighborhoods, including one around the airport.

Here’s what the Trump administration recommends to non-U.S. travelers to Guatemala, namely those from other Central American countries: Stay there and apply for asylum. Don’t even think about continuing north to the U.S. border.

The juxtaposition is absurd but no less so than the agreement the administration struck last week with Guatemala – that it be considered a “safe third country” to which the United States will return asylum seekers if they have not already sought refuge there. If the administration’s contempt for Central Americans fleeing violence, hardship and persecution was not already clear, this new policy clarified it.

The rule, set to take effect in the coming weeks if U.S. or Guatemalan courts don’t block it, is mainly aimed at migrants from El Salvador and Honduras. They constitute the second- and third-largest cohorts of asylum seekers crossing the U.S. southwestern border in recent months, and most of them traverse Guatemala on their trek northward. (The largest cohort is Guatemalans themselves, who accounted for a majority of the more than 100,000 migrants stopped at the border monthly this past spring.)

President Trump, irate at the migrant flow, has used slander – “these are bad people,” he told reporters – and a grab bag of legally dubious deterrent measures. He is right that Customs and Border Protection and other agencies are struggling to handle the tide, which resulted in nearly 700,000 apprehensions in the current fiscal year through June, compared with scarcely 400,000 the entire previous year. But it is morally indefensible to attack a migration problem by putting migrants themselves at risk. That is precisely what the administration’s new move would do.

The United States maintains a safe-third-country agreement with Canada, meaning that asylum seekers can be returned to that country to apply for refuge if they crossed the border from there. That makes sense because Canada is generally safe; Guatemala is anything but. And the retort of acting Homeland Security Secretary Kevin McAleenan, who noted that parts of the United States are also unsafe, is risible. Guatemala’s crime rate dwarfs that of the United States; the homicide rate there is five times higher.

The probable result of the administration’s policy, if it goes into effect, will be to transform legal asylum seekers into undocumented immigrants. They are unlikely to seek refuge in Guatemala, which has no administrative mechanism to process thousands of asylum applications – and which agreed to the deal with the United States only after Trump threatened severe sanctions. Instead, many will likely cross illegally into the United States and live in the shadows.

Trump’s response is to build his border wall, which got a lift last week when the Supreme Court said construction could proceed while challenges to funding it continue in the courts. But walls can be scaled, tunneled under and circumnavigated; Trump’s wall would not stanch the flow of migrants nor improve the conditions that drive them from their countries.