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2. Why was Obama sworn in twice four years ago?
Inauguration Day four years ago also fell on a Sunday.
Obama was visiting Canada so he was sworn in privately on the plane and later attended the public ceremony in Washington, D.C.
Chief Justice John Roberts and Obama misstated the oath on Jan. 20, so the next day, the chief justice readministered the oath.
All presidents take an oath privately before attending the public swearing-in ceremony.