3. Kirsten Nielsen

Kirstjen Nielsen is an American public servant who served as the Secretary of Homeland Security from December 2017 to April 2019 under President Donald Trump. In this role, she oversaw the department responsible for national security, immigration enforcement, and disaster response. Nielsen played a key role in implementing controversial policies, including changes to immigration laws and border security measures. Her tenure was marked by intense debate over immigration practices, particularly the separation of families at the U.S.-Mexico border. She resigned amid criticisms of her department's handling of these issues.