MANCHESTER, N.H.—Marco Rubio went into repetition mode during Saturday night's debate, repeating the same line over and over again to defend against comparisons to Barack Obama.“Let’s dispel with this fiction that Barack Obama doesn’t know what he’s doing,” the Florida senator said. “He knows exactly what he’s doing. He’s trying to change this country.”Rubio would go on to repeat that argument, nearly word-for-word, multiple times over the course of a single exchange with Chris Christie, who said that Rubio's inexperience mirrored Obama's.