Noon-1:30 p.m., Chong Wook Chung, Korean Ambassador. "A Changing Security Architecture in the Northeast Asia and the U.S.-Korea Alliance in the Next U.S. Administration." Institute for Corean-American Studies. 3000 Two Logan Square, Philadelphia.
9:00-10:30 p.m. EDT, third presidential debate, University of Nevada, Las Vegas.
3:00-4:30 p.m., Nate Jones, author of Able Archer 83: The Secret History of the NATO Exercise That Almost Triggered Nuclear War; Thomas Blanton, National Security Archive; and Christian Ostermann, History and Public Policy Program. "Able Archer 83." Wilson Center, 1300 Pennsylvania Ave. NW, Washington.
3:00-5:00 p.m., Megan Rice, Transform Now Plowshares; and Dan Zack, Washington Post Reporter. "Courage and Resistance in a Nuclear Age." Sandy Spring Friends Meeting, 17715 Meeting House Road, Sandy Spring, MD.
Missile Defense Agency, intercept flight test (FTG-15) of the Ground-Based Midcourse (GMD) missile defense system. Vandenberg Air Force Base, Lompoc, CA, and Reagan Test Site, Marshall Islands. This is the first GMD intercept test since June 2014.
6:00-9:00 p.m., Thomas Pickering, former Undersecretary of State for Political Affairs; and Richard Somerville, Scripps Institution of Oceanography, "Bulletin of Atomic Scientists Annual Dinner." Chicago Cultural Center, 78 E. Washington St., Chicago.
Senate Armed Services Committee, hearing on the nomination of Lt. Gen. Samuel Greaves to be Commander, Missile Defense Agency (possible). Location TBA, Senate Office Building, Washington. Webcast on the committee website.