President Donald Trump has made policies for the US-Mexico border, and traffic across it, a central part of his presidency.

The months before he took office and the first months of his term did see reductions in the number of people apprehended at the border, but each of the last three months have seen increases that are reversals of the historical trend.

In July, 18,198 people were stopped crossing the border, up from 16,087 in June, 14,521 in May, and 11,125 in April.

The Customs and Border Patrol’s tally of apprehensions and inadmissible persons at the border in July was 25,031, which was a 16% increase over the 21,656 recorded in June.

Apprehensions at the border are at historical lows, a trend dating back to the Obama administration. But the increases over the last three months are a break from a pattern established in recent years, when arrests would rise during the spring and summer before levelling off or falling during late summer and early fall.

“Violence hasn’t stopped pushing people out of Central America. Nor has poverty. Smugglers haven’t gone out of business. So it makes sense that after an initial pause, the flow of migrants would restart,” Adam Isacson, senior associate for defence oversight at the Washington Office on Latin America, told Business Insider.

Trump has continued to tout his border policies, most recently during remarks at his Bedminster, N.J. golf club, where he is taking a 17-day vacation.

John Moore/Getty Images Immigrants from Central America answer questions from a US border agent after crossing the Rio Grande from Mexico into the US on July 24, 2014, near Mission, Texas.

“I’m very proud of what we’ve done on the border. I’m very proud of Gen. Kelly, what he’s done on the border. One of the reasons he’s my chief of staff right now is because he did such an outstanding job at the border,” Trump said on Thursday. “We’re down 78%. Nobody thought that would be — I mean, in the old days, with other administrations, if you were down 1%, it was considered a big thing. We’re down 78% at the border, and nobody thought that was possible.”

It’s not clear to what his 78% figure refers. The number of apprehensions and inadmissible persons was down 47% in July compared to the same month last year, while the fiscal-year-to-date number was 22% lower than the same period last fiscal year. Since October 2016, when the current fiscal year began, apprehensions at the border are down 36%.

The number of unaccompanied minors, which spiked during a surge of Central American migrants heading for the US in 2014, and the number of family units stopped at the border have also fallen during the first months of this fiscal year but seen a rebound over the last three months.

Homeland Security Department spokesman David Lapan told The Wall Street Journal that it was too soon to tell if the increase in arrests is the result of a seasonal trend or an indication that more and more people will attempt to cross the border illegally.

The declines registered in other months during this calendar year have come as the Trump administration — which allotted money for a border wall and more DHS hires — made no changes to how the border was patrolled.

The drop in apprehensions was attributed in part to Trump’s harsh anti-immigrant rhetoric and promises of stepped up border enforcement.

Inside the US, Immigrations and Customs Enforcement has increased arrests and expanded the ranks of people it is pursuing for deportation.

According to Vice News, the use of “prosecutorial discretion” by ICE prosecutors, under which they dropped cases against undocumented immigrants who had broken no laws or were low-risk, has almost disappeared.

Despite the more muscular effort, the number of actual deportations is still below Obama-era levels.

Lapan, the DHS spokesman, told The Journal that 171,300 immigrants had been removed from the US since the start of the 2017 fiscal year, but roughly 240,000 were removed during fiscal year 2016.

During fiscal year 2012, a peak year for deportations during the Obama administration, an average of about 34,000 people were deported each month; this year has seen an average of about 17,000 people removed each month.

The drop in arrests at the border has been cited as one reason for the decline in deportations, as has the increase in arrests seen during Trump’s first months in office.

With more people in custody, the backlog of cases before immigration courts has increased as well, slowing down the pace of removals.

The shifting numbers do not mean people have stopped fleeing violence and instability in Central America and Mexico, however.

Some Mexicans have headed for Canada, and many people fleeing Central America elected to seek asylum in Mexico — between Trump’s election in November and March, requests spiked by more than 150%, according to Reuters.

During 2016, as Trump campaigned on a platform of harsh anti-immigrant measures, asylum requests in Mexico increased to 8,781 from just under 3,500 in 2015.

The recent rescue of 325 migrants being smuggled in tractor-trailer trucks in Mexico, as well as the death of 10 migrants in a truck in San Antonio, Texas, indicate the people are still making the dangerous trek north.

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