Have to recuse himself and tonight nbc news has word on when Robert Mueller may finish his investigation. The major airport closed down, fears of drones hitting airplanes. Over 100,000 travelers impacted. The hunt tonight for those responsible. Shocking video, the father celebrating a backyard Holiday Party struck and killed by a stray bullet. The mystery gunman at large. Is this the most festive street in america . The holiday display you have to see. Announcer this is nbc nightly news with lester holt. Good evening, everyone. Breaking news tonight, defense secretary james mattis is stepping down leaving a white house increasingly gripped by chaos and erratic upheaval. The last of the senior military officials President Trump brought into his administration and frequently called his generals. Mattis tonight tendering a twopage Resignation Letter pointing to disagreements with the president about the use of military power and a thinly veiled rebuke of mr. Trumps treatment of american a