Homeland Security Department leadership shakeup underway

Heads at the U.S. Department of Homeland Security are rolling in an effort to put in power those comfortable pursuing even more aggressive immigration policies.

Homeland Security Secretary Kirstjen Nielsen submitted her resignation to the president on Sunday. Then, U.S. Secret Service Director Randolph "Tex" Alles was ousted on Monday. Alles, a retired Marine major general, took over the position nearly two years ago.

In a statement, White House Press Secretary Sarah Sanders praised Alles.

"[T]he President is thankful for his over 40 years of service to the country," Sanders said. "Mr. Alles will be leaving shortly and President Trump has selected James M. Murray, a career member of the USSS, to take over as director beginning in May."

President Trump's decision reportedly came before the scrutiny on the Secret Service after a Chinese national was caught trying to enter Trump's private club Mar-A-Lago with thumb drives containing malware.

Nielsen told reporters on Monday that she is preparing DHS for her April 10 departure.

"DHS has a vast array of missions," she said. "I want to make sure that we continue to execute them all with excellence through the transition."

As DHS secretary, Nielsen oversaw the administration's so-called zero-tolerance policy that separated thousands of migrant children from their parents last summer.

Trump asked for her resignation because he was reportedly frustrated by her refusal to carry out his demands to take further actions forbidden by court order or federal law. Yet Nielsen remains publicly supportive of the president's policy priorities.

"I share the president's goal of securing the border," Nielsen said. "I will continue to support all efforts to address the humanitarian and security crisis on the border."

Rep. Jerrold Nadler, a Democrat and the chairman of the House Judiciary Committee, said Nielsen's resignation sent an ominous message.

"Apparently she's not brutal enough for the president," he said. "And she was very brutal."