How Did They Flub That ?? (UPDATED)

The United States Of America becomes the first major nation to inagurate an African American as it’s leader and the moment is incredibly historic. Amazingly though somehow both the President and The Chief Justice managed to flub their lines a little (Obama starting early, Roberts and Obama getting some of the language wrong).

I know its a moment of nerves, but the most historic oath ever filmed and they both manage to flub it ?

UPDATE: Here’s how it looked.