White House officials say Moniz, the energy secretary, will be held back from Obama's speech. The traditional move is aimed at preserving government continuity in case of a catastrophe at the Capitol.
Practically all of the highest federal officials were attending the address, including Vice President Joe Biden, Congress' top leaders and most of the Cabinet. The Senate Historical Office says keeping a Cabinet member at an undisclosed location began in the early 1960s and maybe earlier.
The 69-year-old Moniz is a physicist from the Massachusetts Institute of Technology who became energy secretary last May. He succeeded Steven Chu, who missed last year's address.