One person who was conspicuous at the inauguration of Barak Obama was Secretary of Defense designate, Robert Gates. Apparently, Gates was taken to a secret location, and kept there for the duration of the inauguration, in order to ensure continuity, should something untoward happen at the event. With almost all the others in the line of presidential succession present at the Capitol, Gates was probably in the safest place possible in another undisclosed state, town or bunker. This procedure has been in place and followed for quite some time now to ensure continuity in case of a Nuclear attack or assassination attempt. The successor is chosen in consensus with other members of the parliament.