Former Secretary of State Hillary ClintonHillary Diane Rodham ClintonWill the Horowitz report split the baby? Gabbard commemorates John Lennon's passing by singing 'Imagine' Bannon: Clinton waiting to enter 2020 race and 'save the Democratic Party from Michael Bloomberg' MORE on Monday said that the Trump administration's treatment of migrants will remain unchanged despite Kirstjen NielsenKirstjen Michele NielsenTrump puts Kushner in charge of overseeing border wall construction: report Hillicon Valley: Google to limit political ad targeting | Senators scrutinize self-driving car safety | Trump to 'look at' Apple tariff exemption | Progressive lawmakers call for surveillance reforms | House panel advances telecom bills Minority lawmakers call out Google for hiring former Trump DHS official MORE's resignation as Homeland Security secretary.

“Let's be clear: This administration's dehumanization and cruelty toward migrants will not stop after Kirstjen Nielsen leaves office. It is their principal policy," the 2016 Democratic presidential nominee tweeted.


Trump announced Nielsen's resignation Sunday, promoting Kevin McAleenan to acting secretary of the Department of Homeland Security.


Nielsen was the public face of the Trump administration's "zero tolerance" immigration policy that drew widespread criticism last summer.

The policy resulted in thousands of children being separated from their families at the border.

Several commentators and politicians have said that Nielsen will be remembered primarily for her role in that policy.