The New York Times reported Monday that the head of the U.S. Citizenship and Immigration Services (USCIS), L. Francis Cissna, is also expected to step down soon, though neither the White House nor the agency has confirmed.
Also pushed out Monday was U.S. Secret Service Director Randolph "Tex" Alles. Last week the Administration withdrew the nomination of Ron Vitiello to lead Immigration and Customs Enforcement. McAleenan is a longtime border official who is well respected by many members of Congress and within the administration.
Leading senators from both parties were displeased.
Trump has made a clampdown on illegal immigration a centrepiece of his two-year-old presidency, leading chants of "Build that wall" at his rallies as he has sought to cut back on the number of newcomers entering the United States without proper documentation.
The acting Pentagon chief says he expects the military to be asked by the Department of Homeland Security to do more this year to help with security at the U.S. -Mexico border.
But a larger picture here is the idea that this Trump administration, sources tell me, is really pushing the limits on what's legal for immigration policy. And he didn't like it. She limited what public benefits migrants can receive and put regulations in place to circumvent immigration law and deny asylum to anyone caught crossing the border illegally. Later, she and the president visited part of a rebuilt barrier along the border.More news: Trump warns US Jews Democratic victory could leave Israel isolated
The New York Times reported almost a year ago, in May 2018, that Nielsen was close to resigning after Trump berated her in front of other Cabinet secretaries over increases in the number of immigrants crossing illegally from Mexico. During a Senate Judiciary hearing last month, he refused to say whether Customs had a responsibility to keep migrant children in their custody safe. McAleenan had impressed Trump's inner circle, specifically son-in-law Jared Kushner. More than half were families with children.
In January 2018, Nielsen testified before Congress that the DHS "did not have a policy of family separation" resulting in thousands of migrant children being removed from the guardianship of their parents.
She was seen as someone who didn't have a lot of allies in the White House.
Vitiello got a call that night from senior Trump aide Stephen Miller informing him that he wouldn't be joining the president on his trip to the border the next morning.
Trump has seemed to be grasping at anything to stem the tide of migrants. He claims his predecessor, President Barack Obama, is the one who separated children from their families.
"Well, he's been promising to build a wall for two years, so if I were Mexico, I wouldn't be that anxious", Meyers said of the threats.
O'Mara Vignarajah, head of LIRS, said that may reinforce Trump's interest in clamping down on asylum-seekers.
Nielsen's departure threw into sharp focus just how few full-time leaders are at the sprawling department of more than 240,000 people. "I am pleased to announce that Kevin McAleenan, the current U.S. Customs and Border Protection Commissioner, will become Acting Secretary for @DHSgov".