After the election of US president Donald Trump, Mexico braced for a flood of returning citizens kicked out by the US.

But Trump’s tough stance on immigration has yet to result in a spike in deportations. From February to May, the number of Mexicans the US repatriated fell by 27% from the previous year, according to Mexican foreign minister Luis Videgaray. Overall, deportations were down 12% on the year from February to April, data from the Department of Homeland Security shows.

This drop speaks to the difficulties Trump faces in enacting his “America First” immigration policies. Arresting immigrants is relatively easy compared to deporting them, which often involves a court case.

In just four months, Trump has reconfigured the US’s immigration picture. His attitude alone seems to have deterred many would-be border crossers from attempting to enter the US. And the number of border apprehensions, the best proxy for illegal immigration flows, has fallen considerably since he came into office.

The lower number of deportations is partly a reflection of this decrease. When immigrants are caught near the border, shortly after they enter, it’s easier to quickly send them back home. Indeed, under former president Barack Obama, who focused on going after immigrants with a serious criminal record, most of the deportations in the last years of his administration were made at the border.

But Trump’s approach, which also targets longtime immigrants who have committed minor or no offenses, is resulting in more arrests in the interior of the country. Some of those immigrants have a right to a hearing in immigration courts, which are severely backlogged.

At the current rate, the bottleneck is likely to grow worse, so it’s hard to imagine deportations suddenly swelling.

That doesn’t mean that the wave of deportees the Mexican government was expecting will never materialize. Mexican foreign minister Videgaray, who was speaking at a May 30 conference organized by the Miami Herald, called for perspective. “It’s only been four months and it’s still premature to say these numbers constitute a trend,” he said.

Mexico still needs to be prepared to take its undocumented immigrants back—and to learn to live without the generous remittances they’ve been sending from the US.