WASHINGTON — President Trump’s purge of the nation’s top homeland security officials is a sign that he is preparing to unleash an even fiercer assault on immigration, including a possible return of his controversial decision last summer to separate migrant children from their parents, current and former administration officials said Monday.
Mr. Trump shook up the ranks of his top immigration officials after spending months demanding that they take tougher action to stop the surge in migrant families at the border and seething about what he considers their overly legalistic refusals to do what he has said was necessary.
That anger was underscored on Monday when a judge blocked Mr. Trump’s efforts to force asylum seekers to wait in Mexico while their cases proceed — a practice that immigration advocates called inhumane and illegal. Judge Richard Seeborg of the United States District Court for the Northern District of California ruled that existing law did not give Mr. Trump the power to enforce the policy, known as “migrant protection protocols.”
The immediate targets of the president’s growing fury about the situation at the border were the officials who he saw as insufficiently steely minded: Kirstjen Nielsen, who resigned Sunday as the secretary of homeland security, and Ron Vitiello, whose nomination to permanently lead Immigration and Customs Enforcement was pulled after Mr. Trump remarked that “we want to go in a tougher direction.”
But the longer term effect of the eruption of Oval Office frustration is likely to be a burst of hard-line policies that stand out even in an administration that has pursued an unprecedented series of executive actions and rules changes aimed at reducing legal and illegal immigration into the United States.
In addition to urging Mr. Trump to revisit the idea of family separation, several of the president’s closest immigration confidants have been pushing him to consider even harsher measures.
Those include further limits on who can seek asylum; stronger action to close ports of entry along the Mexican border; an executive order to end birthright citizenship; more aggressive construction of a border wall; and a more robust embrace of active-duty troops to secure the border against illegal immigration.
In an administration that is famous for chaos and last-minute decision-making, it is unclear on which of those policies the president might choose to move forward. But by removing Ms. Nielsen, Mr. Vitiello and perhaps others, Mr. Trump is getting rid of voices who sometimes cautioned him against taking actions they believed to be illegal or unwise.
“There was a perception that Secretary Nielsen was not as committed to the sort of full-throated approach that others in the administration, including the White House, were seeking,” said Seth Grossman, who served as deputy general counsel at the Department of Homeland Security from 2011 to 2015.
He said Ms. Nielsen’s exit and Mr. Vitiello’s step back “signals there is an intention to pursue more aggressive policies.”
Three senior administration officials with knowledge of the president’s conversations over the past several months confirmed that Mr. Trump has repeatedly told aides that he wants to restart the family separation policy. One of the officials said the president had made it clear to aides that he liked Ms. Nielsen personally, but was critical of her job performance. All three officials spoke about the internal discussions on the condition of anonymity.
Stephen Miller, the architect of Mr. Trump’s immigration agenda and one of the president’s closest advisers in the White House, has been an advocate for a modified version of the family separation policy known as “binary choice.”
Others, including Kris Kobach, the former Kansas secretary of state and an informal immigration adviser, and Stephen K. Bannon, the president’s former chief strategist, have also been urging tougher actions.
Under a binary choice policy, which is highly controversial, migrant parents would be given a choice of whether to voluntarily allow their children to be separated from them, or to waive their child’s humanitarian protections so the family can be detained together, indefinitely, in jail-like conditions. Immigration advocates have said the idea is inhumane and would be found illegal by courts.
Ms. Nielsen was the head of the department during the Trump administration’s “zero tolerance” policy last year that led to the separation of thousands of families. More than 2,700 children were separated from their parents at the border under that policy to prosecute anyone caught crossing the border illegally, even those with families seeking asylum on humanitarian grounds.
Mr. Trump eventually relented on the family separations, and a federal judge in California halted them in June. But in January, the inspector general of the Department of Health and Human Services reported that thousands more families might have been separated than previously reported.
While Mr. Trump has been hampered by the law in his efforts to impose some new enforcement policies, there are certain things he can do without congressional approval.
Those include shutting down ports of entries along the southwestern border and slowing down the process for both illegal and legal immigration.
Last month, he closed American field offices abroad that had helped facilitate immigration applications. Mr. Trump has also limited the number of people who can request asylum each day through a process known as “metering,” and he has threatened to shut down traffic lanes and tariff trucks at the ports of entry.
Jonathan Meyer, a former deputy general counsel at the Department of Homeland Security, said the Trump administration will continue to pursue hard-line immigration policies because they are important to the president’s political supporters, who helped fuel Mr. Trump’s success in the 2016 presidential campaign.
“It appears that at times it’s less important in this administration, whether they lose or win in court, than to just say they’ve been able to have done it and have it as a talking point,” Mr. Meyer said. “And have an opportunity to criticize the courts if they lose.”
Mr. Meyer said installing a new secretary at the department will further embolden Mr. Trump.
“He’s willing to move forward and do things even when he knows he’s going to be sued for it and when the legality is in question,” Mr. Meyer said. “If that’s the position you take and if you have people willing to implement that strategy, there’s a lot of things you can do. But eventually you’re going to be hit with a temporary restraining order.”
Mr. Grossman said Mr. Trump’s personnel moves were indeed a signal that the administration would embrace aggressive policies. But he added that Mr. Trump has threatened to enact such policies before, only to back off.
The president could also be stymied by further court rulings blocking his efforts to crack down on immigrants.
On Monday in California, the judge said in his ruling that in addition to violating immigration laws, the protocols did not include “sufficient safeguards” to comply with the Department of Homeland Security’s obligation against returning migrants to places where their “life or freedom would be threatened.”
Immigration advocates hailed the decision, calling it the latest victory in the legal battles with the Trump administration that began when the president imposed a travel ban on several predominantly Muslim countries just days after taking office in 2017.
“Try as it may, the Trump administration cannot simply ignore our laws in order to accomplish its goal of preventing people from seeking asylum in the United States,” said Judy Rabinovitz, the deputy director of the American Civil Liberties Union Immigrants’ Rights Project, who argued the case.
The Trump administration had negotiated the protocols with the Mexican government because of the president’s longstanding anger with so-called catch and release policies in which asylum seekers are temporarily released into the United States while they wait for their court hearings.
The policy of forcing some asylum seekers to wait in Mexico was an effort to stop that from happening. But the court ruling means that the president will have to abandon it, at least for the time being.