I have an OpEd in the Washington Post on March 25, 2021, co-authored with Dr. Tom K. Wong and Jesus Rojas Venzor, that analyzes trends in the encounters with Border Patrol at the US’s southern border. [link here, paywalled]

We look at seasonal trends and a pandemic-associated pause to add nuance to the discourse around “surging” border crossing early in the Biden administration.

An excerpt:

In other words, in fiscal year 2021, it appears that migrants are continuing to enter the United States in the same numbers as in fiscal year 2019 — plus the pent-up demand from people who would have come in fiscal year 2020, but for the pandemic. That’s shown in the first figure, earlier, in which the blue trend line for the five months of data available for fiscal year 2021 (October, November, December, January and February) neatly reflects the trend line for fiscal year 2019 — plus the difference between fiscal year 2020 and fiscal year 2019.

This suggests that Title 42 expulsions delayed prospective migrants rather than deterred them — and they’re arriving now.

That would be consistent with nearly three decades of research in political science. Much of this research has been done since President Bill Clinton’s administration ran Operation Gatekeeper, which tried to keep out migrants by increasing funding and staff for border enforcement. Scholars consistently find that border security policies do not necessarily deter migration; rather, they delay migrants’ decisions to travel and change the routes they take.