On March 14, the day that Kevin McCarthy and 12 House Republicans went to Texas to visit the southern border, the El Paso Central Processing Center for migrants reached capacity. The Republicans heard heartbreaking stories of unaccompanied children, some less than six years old, crossing the border while holding hands. Border agents informed the congressmen that fentanyl traffickers are exploiting the surge in illegal immigration. One agent told John Katko, ranking member on the Homeland Security Committee, that a few of the apprehended migrants appear on the terrorist watch list. Border and immigration personnel are stretched thin. “They’ve never seen anything like this,” McCarthy told me.

Indeed, Homeland Secretary Alejandro Mayorkas projects that the United States faces its largest surge in illegal immigration in two decades. He’s ordered FEMA to assist in taking care of the hundreds of unaccompanied minors who show up daily asking for asylum. Mayorkas and President Joe Biden insist that the previous administration is responsible for a crisis that emerged weeks after Donald Trump left the White House. They couldn’t be more wrong.

What’s happening on the southern border is the most preventable emergency in years. And Joe Biden created it. No matter how often he tells asylum seekers that now is not the time to enter the United States, migrants won’t listen. That’s because the policies he put into place incentivize the dangerous trek. At the same time, Biden has handed the Republicans an issue that will remain long after the $1,400 checks in the American Rescue Plan have been forgotten. And it hasn’t been 60 days since he took office.

Biden’s contradictory messaging won’t relieve the pressure on the border. Sure, he told George Stephanopoulos that his message to migrants is, “Don’t leave your town or city or community.” Mayorkas echoed this sentiment in an interview with CBS. But then he added, “If they do, we will not expel that young child.” That includes tens of thousands of teenagers who may be looking for jobs rather than fleeing persecution.

So the White House says stay put, but if you don’t and border patrol apprehends you, you’ll be housed, clothed, fed, and released if you are under 18. And by the way, we’re laying the groundwork for providing legal status and a path to citizenship for the millions of illegal immigrants already here. That’s not a stop light to border crossers. It’s a yellow light: Proceed with caution.

What did Biden expect? True, he’s maintained a Trump-era rule that allows for the swift removal of adults because of the coronavirus. But he exempted minors from the regulation, creating a massive loophole. And he’s torn up just about everything else that Trump did.

Rich Lowry has documented the rapid undoing of Trump’s successes. The most significant changes were ending the Migrant Protection Protocols — the so-called Remain in Mexico plan that kept asylum-seekers in Mexico while their claims were reviewed — and canceling the “safe-third-country” agreements that required migrants to apply for asylum in the first nation they entered on their way to the United States.

Then there’s the attitudinal difference between the two presidents. Whatever else can be said about Trump, his position on illegal immigration was no mystery. Biden, of course, wants to repudiate every aspect of the Trump presidency, especially its approach to immigration. His demeanor and actions send a dramatic signal that America will be more welcoming.

Even if he says otherwise. Kevin McCarthy, for example, recounted his time at an incomplete section of the border wall. Construction workers had only 17 miles left to finish — but were told to put down their tools as of midnight on January 20. Meanwhile the fence around the U.S. Capitol, complete with razor-wire, still stands. Biden’s position on the two walls delivers a message to both migrants and citizens. But it’s not a consistent message. Nor is it a republican one.

The border calamity is the starkest contrast of the transition from Trump to Biden. It’s also a weak spot for an otherwise popular president. A recent Ipsos poll has immigration tied with health care as the third most important issue in the country. The Engagious/Schlesinger focus group of Trump-Biden swing voters expressed reservations about the current approach to the border. And last week’s CBS News poll showed that Biden is vulnerable: Just 52 percent approved of his handling of immigration, versus 67 percent support on the coronavirus, 69 percent on the vaccine, and 60 percent on the economy.

McCarthy downplays the partisan angle. But there’s no denying Republicans sense a political opportunity. House Republicans went on the offensive when Mayorkas testified before Congress Wednesday. Next week, Ted Cruz and John Cornyn will head to the border. Biden was helped by the absence of immigration from last year’s campaign. It allowed him to focus on the pandemic, the economy, and Trump’s personality. But now, on this subject at least, his luck has run out. And he has only himself to blame.

Matthew Continetti is a resident fellow at the American Enterprise Institute and the founding editor of The Washington Free Beacon. For more from the Free Beacon, sign up free of charge for the Morning Beacon email.