Of Joe Biden’s 39 full months in office, 2024 so far has seen the months with the third, fourth, eighth, and ninth fewest migrants apprehended at the U.S.-Mexico border. April was fourth-fewest.

This was unexpected, since it immediately followed some of the Biden administration’s heaviest months for migration, including the record-setting December 2023. The drop appears to owe to a sustained crackdown carried out by Mexico’s government, with migration agents, national guardsmen, and other security forces blocking migrants’ northward progress.

The governor of Texas, Greg Abbott (R), has been claiming that his state government’s border crackdown reduced migration there and pushed it to states further west. That’s not what the data show.

Since record-setting December, and also since migration dropped in January, Arizona—not Texas—has seen the sharpest percentage drop in migration. Arizona has a Democratic governor, and its state government is not carrying out a severe deterrent policy like Abbott’s $10 billion-plus “Operation Lone Star.” Yet Arizona’s migration reduction is similar. So Texas doesn’t get the credit.

We can zoom in further to look at what has happened to migration in each of Border Patrol’s nine U.S.-Mexico border sectors.

Viewed this way, one of Texas’s five sectors did see the sharpest drop in migration: Del Rio, in mid-Texas, fell 86 percent from December to April; 39 percent from January to April. It is the only Texas sector to have decreased more sharply than the border-wide average.

But Tucson, Arizona—Border Patrol’s busiest sector between July 2023 and March 2024—fell almost as steeply as Del Rio (61% since December and 38% since January).

And after a December-January drop, all other Texas sectors are increasing.

Del Rio’s migration decline was led by super-sharp drops in arrivals from Venezuela, Cuba, and Nicaragua, three nationalities (along with Haiti) whose citizens the Mexican government allows the Biden administration to deport into Mexico under its May 2023 post-Title 42 “asylum ban” rule.

Deportation into Mexico without allowing a chance to seek asylum is almost certainly illegal: a federal judge already struck this part of the rule down (it remains in place pending appeal). It’s possible that this practice—more than Texas’s concertina wire, buoys, and soldiers—may have affected the choices these nationalities’ migrants made in Del Rio since January.

Border-wide between January and April, for every Cuban, Haitian, Nicaraguan, or Venezuelan migrant who crossed the border irregularly (43,040), more than five instead arrived via legal channels: either the “CBP One” app (about 120,000) to make appointments at ports of entry, or the Biden administration’s humanitarian parole program (about 108,000) for these nationalities.

In Tucson, no nationalities declined as steeply as did Venezuelans, Nicaraguans, and Cubans in Del Rio. But the drop has happened across the board, with only modest increases in apprehensions of Colombians and Peruvians.

From what we know of the month of May so far, migration along the border could be declining even further. Twitter reports from the San Diego and Tucson Border Patrol sector chiefs have showed both regions declining over the past two weeks. The El Paso municipal government’s “migrant crisis” dashboard is also showing flat, even slightly reduced, numbers of encounters there.