If you don’t put a fence around your swimming pool, and a kid falls in, you can be held liable.

And if you don’t put a fence around your country, and migrants suffer harm trying to get in, your government is liable.

The analogy isn’t perfect, of course. Children don’t know any better, whereas most illegals are adults who know they are taking risks and are responsible for the consequences of their decisions. But in both cases the concept of the “attractive nuisance” applies: If strangers might trespass and harm themselves, you have a responsibility to take some minimum steps to secure your property.

We saw some of the consequences of a border unsecured against trespass recently in Del Rio, Texas. Our main concern, of course, must be the harm to the nation. The mass arrival of illegal aliens gaming the asylum system to gain release and disappear into the country should not be tolerated. The harm to American workers, American taxpayers, and American sovereignty is reason enough for muscular border enforcement.

But as civilized people we cannot ignore the harms caused to prospective illegal aliens themselves by the Biden administration’s feckless and contradictory immigration policies.

The Biden campaign put forward an immigration plan that was all but guaranteed to supercharge future illegal immigration: the termination of vital border-control strategies implemented by the Trump administration, like the Remain in Mexico program; a ban on the deportation of illegal aliens except in the most extreme cases of terrorism, murder, and the like; and amnesty for all illegal aliens who were here as of three weeks before Inauguration Day.

While the formal amnesty requires the approval of Congress (and the Senate parliamentarian recently nixed the inclusion of an amnesty for “only” 8 million illegals in the $3.5 trillion budget reconciliation bill), Biden as president has kept most of his other border-weakening promises. Deportations from the interior of the country have declined precipitously, the immigration (i.e., non-Customs) functions of ICE have been all but abolished, and almost all illegal aliens accompanied by someone under 18 are released into the country, whence they’re extremely unlikely to ever be deported.

The predictable result—predictable to all but the Biden administration and its various allies and auxiliaries—has been a migration emergency. Apprehensions of illegal aliens (or “encounters,” as they’ve been re-christened since January 20) leapt up following the new administration’s installation and are now running at about 50,000 a week. More than half are being released into the country.

Not only have the numbers been rising, but the source countries have diversified. No longer are Mexico and the so-called Northern Triangle countries of Central America (Guatemala, Honduras, and El Salvador) the near-exclusive source of illegal immigration. As word has spread that the border is far more permeable now than it was under the Bad Orange Man, the number and share of border-jumpers from elsewhere have risen, with fully 30 percent of all “encounters” in August coming from farther afield.

Among those who took President Biden up on “La Invitacion” (what smugglers in Mexico have dubbed Biden’s approach to immigration) are Haitians. From the Biden inauguration through August, about 25,000 Haitian illegal aliens have been “encountered” on the Mexican border, of whom about 23,000 were released into the U.S. And not just any Haitians, but Haitians who left their country years ago and settled in the farthest reaches of South America, especially Chile and Brazil, which gave Haitians legal status and work permits.

When my colleague Todd Bensman asked one such Haitian, in Costa Rica on his way north, what life was like for him in Chile, the migrant responded, “A thousand times better” than Haiti. When Todd then asked why he left and headed for the U.S. border, he answered, “Because life in the United States will be a million times better.”

The Haitians who swarmed Del Rio recently (mainly because the cartel that controls the Mexican side doesn’t bother migrants, unlike other sites on the border) had every reason to believe that they would follow in the footsteps of their earlier countrymen, and citizens of every other country on earth, and either be released into the U.S. or, at worst, be pushed back into Mexico to try again.

But the enormous numbers all at once, overwhelming the Border Patrol’s ability even to rubber-stamp them before letting them go, combined with Fox News’s drone camera footage of the growing “Bidenville” under the international bridge in Del Rio, forced the administration to change course—a little. The majority of the Haitian illegals are still being released into the U.S., never to be seen again, but some of the single men are being repatriated to their country of nationality rather than just sent back across the river.

And return to Haiti is something the Haitians formerly of Chile and Brazil really don’t want. In fact, if it had been clear from the beginning that jumping the border would result in return to Haiti, rather than release into the U.S., few if any of them would have attempted it. The aversion to returning to their home country is so great that once the deportations started from Del Rio, at least 2,000 Haitians returned across the river and bought bus tickets back to Mexico’s southern border, where they had been awaiting a decision by Mexican authorities on whether they could remain.

Thus the cruelty of Biden’s approach to immigration. Rather than keep Trump’s successful policies in place, he reversed almost all of them, luring settled Haitians (among many others) to sell everything and leave South America. Then, when the White House realized what a political disaster was in the making, DHS sent at least some of the Haitians back to their unfortunate country. So some significant number of Haitians settled in South America ended up back in Haiti only because of Joe Biden.

But the Biden administration’s transformation of the U.S. border into an attractive nuisance isn’t limited to Haitians. His policy of easy release with almost no likelihood of deportation entices people worldwide to take great risks. For prospective illegal aliens from beyond Central America, Ecuador is often the jumping off point for the trek north, given its loose border policies. But crossing from South America to North America requires passing through the lawless jungle of the Darien Gap in eastern Panama, with no roads or settlements but plenty of bandits and venomous snakes. As the Associated Press reports, “Children have reportedly died in the jungle, and some pregnant women have given birth. Migrants say they have seen skulls and cadavers along the routes that cross the Darien.”

Even the so-called Dreamers—illegal aliens who came here as minors—are victims, if not specifically of Biden’s policies (though he is creating future Dreamers by the tens of thousands), of our longstanding unwillingness to enforce immigration laws. It really is tragic that a young person could grow up here thinking he was an American only to find out when he applies for a driver’s license or college admission that he’s an illegal alien.

The left’s response to this is more cowbell: amnesty all the way down. But the real solution is to build a fence around the swimming pool, as it were, by making sure it’s simply not possible for illegal-alien parents to live here undisturbed for so long that the infant they brought with them graduates high school.

No matter how effective our immigration controls, some people will still risk life and limb (and children) in places like the Darien Gap in an attempt to immigrate illegally—but nothing like the numbers we’re seeing now, lured by Joe Biden’s weakness. Our history of ambivalent and half-hearted enforcement of immigration laws—embraced and institutionalized by the Biden administration—has many costs. Among those who bear the costs are often migrants themselves.

Mark Krikorian is the executive director of the Center for Immigration Studies.