USSS Director Randolph Alles, a retired Marine Corps major general who was appointed two years ago, is on his way out the door just the day after the head of the Department of Homeland Security, Kirstjen Nielsen, resigned under pressure on Sunday night. Alles reported to her. More ousters of agency heads within DHS are possible and a number of key positions remains vacant. An administration official said the decision to seek the resignation of Alles was made 10 to 14 days ago — before a March 28 incident in which a Chinese woman was arrested at Mar-a-Lago without an invite, touching off security concerns.