Joe Biden’s presidency is over, but we are only now beginning to understand the full scale of the immigration surge that he oversaw. Immigration was so rapid over the last four years that the Census Bureau had trouble keeping up. The agency recently announced that net international migration for 2022 and 2023 was not a combined 2 million, as it had originally reported, but 4 million! For 2024 alone, the Census now says that net migration was 2.8 million, which is more than double the number in any single year this century prior to Biden’s taking office.

The January data from the Census Bureau’s Current Population Survey (CPS) offers the first estimate of the foreign-born that is adjusted for some of the prior undercount. As detailed in a new report by my colleagues Steven Camarota and Karen Zeigler, the foreign-born population in the CPS has reached a record 53.3 million, up from 45 million four years ago. (These numbers include illegal immigrants, with some caveats that the authors discuss.)

The foreign-born share of the population now stands at 15.8 percent, which eclipses the highs of the Great Wave at the turn of the 20th century. As the report notes, the Census Bureau projected two years ago that the foreign-born share would not hit 15.8 percent until 2042. That trend has apparently accelerated by 17 years.

The lesson is that policy matters, especially at the border. Camarota and Zeigler estimate that nearly two-thirds of the increase in the foreign-born population over the last four years was due to illegal immigration, and yet illegal border-crossings have since fallen dramatically under President Trump. It’s not difficult to see why. Trump reversed the Biden policies of catch and release and mass parole, secured better cooperation from Mexico, and empowered interior enforcement.

In light of that success, recall how Biden administration officials denied their own culpability once the border crisis developed. The surge is due to seasonality, they said, or maybe to a resumption of prior trends interrupted by Covid, or to “push factors” beyond the administration’s control, or to the failure of amnesty legislation in 2013, or to the sinking of the Lankford-Schumer bill in 2024. The excuses piled up. All of them have since proven empty.

Still, it’s not just policy itself that matters but policy expectations as well. When migrants heard candidate Biden’s promises to weaken enforcement, in 2020, they began streaming to the border even before he was inaugurated. Similarly, the new Trump administration’s early success is due not only to physically turning away attempted border crossers but also to the perception among would-be migrants that the journey is no longer worth making. To keep that perception a reality, the administration will need to vigorously and consistently enforce the law while steeling itself for the legislative and legal battles on the horizon.