Homeland Security Secretary Kirstjen Nielsen walks past concertina wire on her way to view the border fence.
Homeland Security Secretary Kirstjen Nielsen in November during a visit to San Diego’s border with Mexico. Photo by Chris Stone

Secretary of the U.S. Department of Homeland Security Kirstjen M. Nielsen resigned Sunday night in a letter to President Trump saying it was the right time “to step aside.”

The letter, which Nielsen posted on her Twitter account, said, “I hope that the next Secretary will have the support of Congress and the courts in fixing the laws which have impeded our ability to fully secure America’s borders and which have contributed to discord in our nation’s discourse.”

Trump thanked Nielsen for her service on Twitter and announced he has appointed current U.S. Customs and Border Protection Commissioner Kevin McAleenan as acting DHS secretary.

“I have confidence that Kevin will do a great job!” Trump wrote.

Nielsen has been under fire by human rights and immigrant advocates who roundly criticized her border policies, in particular the separation of families seeking U.S. asylum and concerns over the housing and treatment of migrant children.

“@SecNielsen separated mamas from their babies and locked little children in cages. I’m not sorry to see her go,” Sen. Elizabeth Warren (D-Mass.) wrote on Twitter. “I only wish she’d been fired long ago, before she ever had a chance to resign.”

Nielsen’s resignation letter:

Mr. President,

I hereby resign from the position of Secretary of the U.S. Department of Homeland Security (DHS), effective April 7th 2019. It has been my great honor to lead the men and women of the Department as its sixth Secretary. I could not be prouder of and more humbled by their service, dedication, and commitment to keep our country safe from all threats and hazards. I join all Americans in thanking them for their sacrifices and those of their families.

For more than two years of service beginning during the Presidential Transition, I have worked tirelessly to advance the goals and missions of the Department. I am immensely proud of our successes in transforming DHS to keep pace with our enemies and adversaries — whether it is in cyberspace or against emerging threats from new technologies.

Despite our progress in reforming homeland security for a new age, I have determined that it is the right time for me to step aside. I hope that the next Secretary will have the support of Congress and the courts in fixing the laws which have impeded our ability to fully secure America’s borders and which have contributed to discord in our nation’s discourse. Our country and the men and women of DHS deserve to have all the tools and resources they need to execute the mission entrusted to them.

I can say with confidence our homeland is safer today than when I joined the Administration. We have taken unprecedented action to protect Americans. We have implemented historic efforts to defend our borders, combat illegal immigration, obstruct the inflow of drugs, and uphold our laws and values. We have responded decisively to record-breaking natural disasters and helped Americans rebuild. We have prevented the disruption of U.S. elections and guarded against foreign interference in our democracy. We have replaced complacency with consequences in cyberspace, we are holding digital intruders accountable, and we are stepping up our protection of American networks. We have thwarted terrorist plotting against our homeland and launched new efforts to block terrorists and criminals from reaching our shores. And we have ramped up security measures to make it harder for our enemies and adversaries to attack us, whether it is with drones, chemical and biological weapons, or through other means.

Thank you again for the privilege to serve the American people and to lead the outstanding men and women of the Department of Homeland Security. Supporting these patriots has been the honor of a lifetime.

Sincerely,

Kirstjen M. Nielsen