Arrests for illegal border crossings have dropped more than 40% during the three weeks that asylum processing has been suspended, the Homeland Security Department said Wednesday.

The announcement comes just one day before President Joe Biden is set to debate former President and presumptive Republican presidential nominee Donald Trump in what is expected to be a crucial moment in the election campaign.

Biden is considered especially vulnerable with voters when it comes to immigration. Trump has hammered him repeatedly on border security by painting a picture of the border as out of control and migrants as a threat to the nation’s security and economy.

Biden has both sought to crack down on new arrivals at the border and to offer new immigration pathways.

The restrictions he announced at the beginning of June cut off asylum access when arrivals at the border reached a certain number, infuriating immigration advocates who say the policy differs little from what Trump attempted. Then a few weeks later Biden announced a new program aimed at undocumented spouses of American citizens who had been in the country for a decade or more that could ultimately provide them a pathway to citizenship.

The figures announced Wednesday by the Department of Homeland Security show that the Border Patrol’s average daily arrests over a seven-day period have fallen below 2,400, down more than 40% from before Biden’s proclamation took effect June 5. That’s still above the 1,500 mark needed to resume asylum processing, but Homeland Security says it marks the lowest number since Jan. 17, 2021, just before Biden took office.0

Last week, Customs and Border Protection said in its monthly release of statistics that border arrests had fallen 25% since Biden’s order took effect, indicating they have decreased much more since then.

The monthly data releases are a closely watched metric of border security and how many people are coming to the southern border of the U.S. The numbers reached a record high last December before falling roughly in half in January and staying in that range throughout the spring. A large part of that decrease was believed to be due to Mexican enforcement on its side of the border.

Homeland Security Secretary Alejandro Mayorkas visited the Tucson, Arizona, sector Wednesday. That sector has been the busiest corridor for illegal crossings during much of the last year. U.S. authorities say the seven-day daily average of arrests in the sector was just under 600 on Tuesday, down from just under 1,200 on June 2.

Mayorkas declared the new rule limiting asylum a success during his visit.

“These actions are changing the calculus for those considering crossing the border,” the secretary told reporters.

Under the asylum suspension, which takes effect when daily arrests are above 2,500, anyone who expresses fear or an intention to seek asylum is screened by a U.S. asylum officer but at a higher standard than currently used. If they pass the screening, they can pursue more limited forms of humanitarian protection than asylum, including the U.N. Convention Against Torture.

Immigration advocates have sued to stop the restrictions.

(AP)