With, President Trump said Sunday he would appoint Customs and Border Patrol Commissioner Kevin McAleenan to temporarily lead DHS amid renewed efforts to clamp down on migrants crossing the the U.S.-Mexico border.
Here's s a closer look at McAleenan.
A CBP veteran since 2006, McAleenan has previously held several leadership roles in the law enforcement agency tasked with securing the U.S. border. McAleenan was sworn in as CBP commissioner in March 2018, and prior to his confirmation he served both as acting and deputy commissioner of the agency. McAleenan manages the agency's budget of over $13 billion and, according to his official biography, "oversees the largest law enforcement agency and the second-largest revenue collecting source in the federal government."
Prior to entering the federal government, McAleenan practiced law in California. He attended the University of Chicago Law School and Amherst College.
His views on immigration
McAleenan is a staunch supporter of the president's long-promised border wall. During a visit to the southern border, McAleenan called the wall "formidable" and touted its impact on the security of the southern border. The CBP commissioner has vowed to "restore integrity to our immigration system" and has faulted the current legal system for the rise in migrant crossings.
"The increase in family units is a direct response to the vulnerabilities in our legal framework where migrants and smugglers know that they will be released and allowed to stay in the U.S. indefinitely pending immigration proceedings that could be many years out," he said. "This is due to court orders that undermine the integrity of our immigration system."
He insists that Congress must impose stricter immigration laws, telling CBP officials at a March event in El Paso, Texas that "legislative relief, changes in the law, and closing the vulnerabilities in our legal framework" are the "only way" that the flow of migrants across the border will be reduced.
McAleenan previously told "CBS This Morning" that CPBto handling children in its custody after a child died while in his agency's custody last year. He argued that more resources are needed to care for children in detention centers.
"We need help from Congress. We need to budget for medical care and mental health care for children in our facilities and I'm committed to improving our conditions, even as we work on the broader problems — border security, and of course solving the issues in our legal framework that are inviting these families and children to make this dangerous journey," McAleenan said at the time.
McAleenan has also urged Mexico to help stop the flow of criminals entering the U.S., saying at a roundtable event last week: "We need partnership from Mexico on these flows in attacking the criminals that are exploiting these individuals and, really, the ones that are profiting from this entire cycle."
What Trump says
Just days ago, during a visit to Calexico, California where the president toured a portion of border wall being rebuilt, Mr. Trump commended McAleenan for the work he's done as CBP commissioner.
"We have spent a lot of time together. And, Kevin, you're doing a great job. And thank you very much for being here. Appreciate it." Mr. Trump said at a roundtable event.
He later tweeted that "confidence that Kevin will do a great job!" when news broke that Nielsen would resign.
What Democrats say
Democrats have been roundly critical of the president's pick. Congressional Hispanic Caucus Chairman Joaquin Castro slammed McAleenan's appointment as "deeply disturbing," citing his failure to notify Congress about the death of a child in CBP custody.
"He cannot be trusted as Acting DHS Secretary based on his record of prioritizing Trump's harmful policies that undermine national security and the economy, and hurt vulnerable families and children at the border," added Castro in a statement.
Other Democrats have voiced similar concerns that Nielsen's replacement would be a stronger advocate for strict immigration policies. Senate Democratic Whip Dick Durbin said in a statement that Nielsen's departure "would be encouraging were we not warned that President Trump is looking for a successor who will engage in even harsher tactics."
Durbin added, "There appears to be no limit to the cruelty of this Administration when it comes to its failed immigration policies."
Former Secretary of State Hillary Clinton echoed that sentiment, tweeting Monday: "This administration's dehumanization and cruelty toward migrants will not stop after Kirstjen Nielsen leaves office. It is their principal policy."
Despite current concerns voiced by some Democratic lawmakers, McAleenan did receive broad bipartisan support when he was confirmed to his current role.