President Trump last week urged Kevin McAleenan, whom he was about to name as acting secretary of homeland security, to close the southwestern border despite having just said that he was delaying a decision on the step for a year, according to three people briefed about the conversation.
It was not clear what Mr. Trump meant by his request or his additional comment to Mr. McAleenan that he would pardon him if he encountered any legal problems as a result of taking the action. Federal judges have already blocked the administration’s attempts to limit asylum seekers who illegally enter the country, and it is not likely Mr. McAleenan would have ended up in jail if he had followed the president’s directive.
One of the people briefed on the conversation said it was unclear whether Mr. Trump had intended the comments to Mr. McAleenan as a joke. But the conversation, which took place during the president’s visit to the border town of Calexico, Calif., alarmed officials at the Department of Homeland Security who were told of it, according to the people familiar with the comments.
A day before his trip to the West Coast, Mr. Trump had retreated from his threat to close the border within days. Instead, he told reporters, he was issuing a “one-year warning” if Mexico did not halt illegal immigration and drug trafficking. Privately, however, he was still pushing his aides to halt the flow of asylum seekers across the Mexican border.
Besides Mr. McAleenan, who was then commissioner of Customs and Border Protection, Mr. Trump was accompanied on the trip by Kirstjen Nielsen, at the time the secretary of homeland security.
Ms. Nielsen had earlier refused to carry through with Mr. Trump’s desire to close the border, telling him it was illegal. But the president encouraged Mr. McAleenan to disregard Ms. Nielsen and enforce the move himself. Two days later, Ms. Nielsen submitted her resignation under pressure from Mr. Trump, and the president appointed Mr. McAleenan acting secretary of homeland security.
A White House spokesman declined to respond to requests for comment on the conversation. Tyler Q. Houlton, a spokesman for the Department of Homeland Security, did not specifically address it.
“At no time has the president indicated, asked, directed or pressured the acting secretary to do anything illegal,” Mr. Houlton said. “Nor would the acting secretary take actions that are not in accordance with our responsibility to enforce the law.”
Mr. Trump’s desire to close the border, despite the legal impediments, was a factor in the forced resignation of Ms. Nielsen. It was one of a number of instances in which Ms. Nielsen believed she was being asked to engage in conduct that violated laws, according to several people with knowledge of those discussions.
His conversation with Mr. McAleenan was one of the most acute examples of Mr. Trump’s desire to use any means to stem the tide of immigration into the United States, and a reminder of what he would like to see as the unilateral powers of the presidency.
Mr. Trump has been growing increasingly agitated about images of the border he has seen on television, and distressed by the number of immigrants entering the country from the southern border with Mexico. He has ramped up his messaging against not just illegal immigration but legal immigration, mocking asylum seekers as fakes who are pretending to face difficult conditions to ease their passage across the border.
More undocumented immigrants were apprehended along the southern border in March than in any month since 2007, Customs and Border Protection reported this week.
Publicly, Mr. Trump has not revisited closing the border. But in statements to reporters and on Twitter, he has repeatedly excoriated Democrats over immigration policy.
“I’m going to have to call up more military” to the southern border, Mr. Trump told reporters during a visit to San Antonio this week. “Our military, don’t forget, can’t act like they would normally act because if they got a little rough, everybody would go crazy.”
On Friday, Mr. Trump wrote on Twitter that he was still considering placing undocumented immigrants in so-called sanctuary cities “due to the fact that Democrats are unwilling to change our very dangerous immigration laws.” That statement contradicted his own aides, who described the proposal as a “suggestion that was floated and rejected, which ended any further discussion.”