Kirstjen Nielsen, Trump's Homeland Security Secretary, Is Stepping Down

Another key figure is leaving the Trump administration. On Sunday, Homeland Security Secretary Kirstjen Nielsen announced she will resign. Nielsen has led the department since December 2017, overseeing operations through several controversial immigration crises.

Trump confirmed her departure in two tweets on Sunday evening. "Secretary of Homeland Security Kirstjen Nielsen will be leaving her position, and I would like to thank her for her service..." Trump wrote. "...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!"

Prior to taking her post at the Department of Homeland Security, Nielsen worked in the George W. Bush White House as a Special Assistant to the President for Prevention, Preparedness, and Response, a position on the White House Homeland Security Council. She's held several positions under the Trump administration, including as John Kelly's chief of staff while he was the secretary of Homeland Security, according to Politico.

In her capacity as secretary of Homeland Security, Nielsen was probably most well-known for backing the Trump administration's "zero tolerance" immigration policy, which resulted in thousands of children being separated from their families at the U.S-Mexico border.

Nielsen joined the president in California on Friday as part of a multi-state tour meant to help the department address the ongoing immigration crisis as the U.S.-Mexico border, according to a DHS press release. As part of the visit, the pair visited a section of the border wall that was newly built. During the trip, Nielsen blamed the country's immigration problems on legislative and judicial loopholes.

“No matter what we do, it’s clear that the only way to truly fix this crisis is with legislation. Outdated laws and misguided court decisions have created an illegal fast-pass into America," Nielsen said during her visit, according to a DHS press release. "These loopholes are the main cause of today’s emergency…they are enormous ‘pull’ factors to the United States…and closing them is the only surefire way out of this emergency."

It was not immediately clear on Sunday when Nielsen would formally leave her post. Neither she nor DHS released a public statement following Trump's formal announcement.

Nielsen oversaw DHS at a time when the president repeatedly doubled down on his demand that a new border wall be built along the U.S.-Mexico border — a key piece of his 2016 presidential campaign platform. Nielsen's resignation comes as the Trump administration remains embroiled in an effort to secure funding for the new wall. Some of those funds may come from a February national emergency declaration, but whether or not that will be a viable option in the long-run remains unclear.

On Sunday, some Democrats were quick to praise Nielsen's resignation.

"About time," tweeted Sen. Elizabeth Warren, a 2020 presidential candidate. "@SecNielsen’s legacy of tearing innocent families apart will follow her for the rest of her life—and she should be ashamed of the role she played. She was completely unqualified to lead @DHS—and that's why I voted against confirming her."

Although abrupt, as The New York Times reports, political analysts have speculated for months that Nielsen would soon leave her post. On Sunday, it was too early to predict the long-term ramifications of her departure.