Kirstjen Nielsen Resigns After Clashes With Trump: Here's a History of Disputes Between the President and DHS Secretary

Department of Homeland Security Secretary Kirstjen Nielsen stepped down from her role on Sunday, in a long-expected move reportedly fueled by her clashes with President Donald Trump over immigration and border security policies.

Trump announced in a Sunday tweet that Nielsen would leave the White House and that he had appointed Customs and Border Protection Commissioner Kevin McAleenan as Acting DHS secretary.

"Secretary of Homeland Security Kirstjen Nielsen will be leaving her position, and I would like to thank her for her service," the president tweeted. "....I am pleased to announce that Kevin McAleenan, the current U.S. Customs and Border Protection Commissioner, will become Acting Secretary for @DHSgov. I have confidence that Kevin will do a great job!"

Although it not yet known whether Nielsen decided to leave voluntarily or whether the president forced her to resign, the move comes after a history of disagreements with the president over the handling of illegal immigration and border security.

"This afternoon I submitted my resignation to @POTUS and thanked him for the opportunity to serve in his administration. It's been an honor of a lifetime to serve with the brave men and women of @DHSgov," Nielsen tweeted on Sunday, alongside her full resignation letter. "I could not be prouder of and more humbled by their service, dedication, and commitment to keep our country safe from all threats and hazards."

Nielsen said in a separate tweet that she would remain with DHS until Wednesday, April 10.

Nielsen, who for more than year was responsible for implementing Trump's immigration policies, often defended the president's tough immigration policies. But that didn't stop the president from repeatedly criticizing her in Cabinet meetings, and to other Oval Office officials. In light of Nielsen's departure, here's a brief look at Nielsen and Trump's rocky history during her White House tenure, which began after she was confirmed in December 2017.

Immigration officials told The Washington Post last May that Trump had berated Nielsen in the Oval Office about her performance and her failure to minimize illegal border crossings to his standards. According to the officials, when then-White House Chief of Staff John Kelly attempted to defend the DHS secretary, Trump pointed out that border numbers were lower under Kelly and demanded to know why she couldn't keep them down.

The uncomfortable meeting came weeks after Trump had criticized Nielsen during another Cabinet meeting after he found out that the number of immigrants caught crossing illegally from Mexico exceeded 50,000 for the second month in a row.

"Why don't you have solutions? How is this still happening?" the president reportedly said, according to The Post, "We need to shut it down. We're closed." According to The Post, Trump was so furious that White House aides present said others at the meeting were seen grimacing and fidgeting in their seats amid the rant.

At the time, The New York Times reported that two of Nielsen's colleagues said she told them she had drafted a resignation letter but decided against submitting it. DHS spokesperson Tyler Houlton said such claims were false.

A senior White House official told The Post in May 2018 that Trump had always complained to colleagues about how Nielsen was "not tough enough" and reminded them she had been a "George W. Bush person." Nielsen had previously served in former President George W. Bush's administration as a special assistant to the president, among other roles.

One month later, in June 2018, Trump offered Nielsen rare praise during a meeting with Republicans before echoing the same sentiments in a tweet in which he said she "did a fabulous job yesterday at the press conference explaining security at the border and for our country, while at the same time recommending changes to obsolete & nasty laws, which force family separation."

But the praise was short-lived. In November, reports began to emerge of Trump telling advisers that he was considering removing Nielsen from her role and that he wanted her out as soon as possible because of her substandard performance on immigration enforcement.

Secretary of Homeland Security Kirstjen Nielsen, right, speaks with President Donald Trump as they meet to discuss fighting human trafficking on the southern border, in Washington, D.C., on February 1. On April 7, Nielsen announced she would resign as secretary of the Department of Homeland Security. Jim Watson/AFP/Getty Images