Chief Justice John Roberts got it right this time -- but President Barack Obama appeared to stumble over the word "states" during his ceremonial swearing in.

In front of hundreds of thousands gathered to watch, Obama stammered briefly over "states" as he repeated back the words "the office of president of the United States."

Obama had already been officially sworn in for a second term on Sunday, in accordance with the Constitution, which requires presidential terms to begin on Jan. 20.

In 2009, it was Roberts who famously flubbed Obama's official swearing in. As a result of that mistake, Roberts and Obama repeated the presidential oath in a private ceremony to ensure there were no constitutional issues.