Acting Homeland Security Secretary Kevin McAleenan is leaving his job, President Donald Trump announced on Twitter.

“We have worked well together with Border Crossings being way down. Kevin now, after many years in Government, wants to spend more time with his family and go to the private sector,” Trump wrote.

“Congratulations Kevin, on a job well done! I will be announcing the new Acting Secretary next week. Many wonderful candidates!”

His departure is the latest in what several analysts say is a record turnover level for a first-term president. It also highlights Trump’s struggle to keep anyone in the top DHS role as he pursues a hardline immigration policy.

“Kevin now, after many years in Government, wants to spend more time with his family and go to the private sector,” Trump wrote from Air Force One as he headed to his second campaign rally in as many nights.

Picking another acting official and not making a formal nomination, something he says gives him an undefined amount of “flexibility,” would also avoid adding to the Senate’s pre-holiday agenda.

Lawmakers and Trump must still reach a spending deal by Nov. 21 to avert another government shutdown — and any long-term agreement will have to overcome an expected partisan fight over funding for his proposed southern border wall.

Six months at the helm

McAleenan took over the role as acting secretary after Trump pushed out Kirstjen Nielsen, who formally resigned from the position in April. Unlike Nielsen, McAleenan is a career law enforcement official.

McAleenan has been at the helm of numerous immigration policies that have curbed illegal immigration at the southern U.S. border and made it harder for migrants to apply for asylum. Among those policies, criticized by Democrats, is the so-called “Remain in Mexico” program that has sent more than 50,000 migrants to Mexico to wait for their immigration cases to be processed in U.S. courts. 

He has also overseen agreements with the governments of Mexico, El Salvador, Guatemala, and Honduras that seek to collectively curb migration to the Southern border. While only Mexico’s agreement has been implemented, experts say they’re seeing its effects.

McAleenan recently hinted he might be headed out the door, revealing in a Washington Post interview that he had grown frustrated over his inability to keep DHS from being used as a political tool.

“What I don’t have control over is the tone, the message, the public face and approach of the department in an increasingly polarized time,” he said in an Oct. 1 article.  “That’s uncomfortable, as the accountable, senior figure.”

McAleenan issued a tweet thanking Trump for the opportunity to serve in his role.

“With his support, over the last 6 months, we have made tremendous progress mitigating the border security and humanitarian crisis we faced this year by reducing unlawful crossings, partnering with governments in the region to encounter human smugglers and address the causes of migration and deploy additional border security resources,” he wrote. “I will work with the White House and DHS leadership teams on a smooth transition and remain forever grateful to the men and women of the Department for the steadfast efforts to secure our country.”

In addition to immigration programs, DHS also oversees a number of agencies including the Transportation Security Agency, the Secret Service, and the U.S. Coast Guard as well as managing the Federal Emergency Management Agency.